I have wireless chip inside me that broadcasts signal to my friend who can read the frequency on computer.
First of all, you use the term 'frequency' in a way that indicates you don't have a particularly good grasp of electromagnetic radiation. You happen to use it in the same way that people who come to this forum to look for
emotional support to their pet theories, which can only be responded sanely with ridicule. This forum is a rare one dedicated to
rational discussion between engineers and scientists and likeminded hobbyists, so you can hopefully understand why the reaction to someone wanting everyone to please them and drop all logic and rationality, is reacted to so strongly.
I am taking a risk, and assuming that this is not the case with you, and is just an unfortunate communications issue.
First of all, basically everything radiates electromagnetic waves all the time; just see the
electromagnetic spectrum. Frequency determines the type of the radiation, as well as what kind of reactions the radiation can have with matter. Intensity is the amount of radiation, and to be useful for communications, it has to be high/strong enough to not be absorbed by intervening matter.
You can exclude ionizing radiation by going through an airport security check. If you do trip it, you'll go through a wringer, because ionizing radiation will damage your tissues and is basically deadly; you'll probably be treated as a potential terrorist, and afterwards have to go through chelation in a hospital (a process of trying to remove the radiation source from your body, especially from your blood flow). Every time you have an x-ray taken, you do get a dose of it; and similarly when you go for a long flight (where the plane flies at altitudes above 30,000 feet or so). So ionizing radiation of various kinds (frequencies) exists in nature, but is not intense enough to worry about, our bodies have evolved to deal with it. Russians do like to use polonium (a rare metal that emits ionizing radiation) to kill people in a signature way, though.
(Strictly speaking, not all ionizing radiation is electromagnetic radiation. There is also alpha radiation consisting of helium nuclei; beta radiation consisting of electrons; neutron radiation consisting of neutrons; and cosmic rays, which can be either high-energy photons (electromagnetic radiation) or some more exotic high-energy particles. Still, anything like this inside your body intense/strong enough to be measurable above the background noise is Bad News; and definitely would need recognizable exotic detectors to be detected, something off a physics laboratory or hospital radiation ward.)
If it was visible light, you'd be able to see it. If it was infrared or ultraviolet light, it'd cook your tissues.
Infrared is absorbed by tissue (and naturally converts to heat), so those are out. Frequencies below 10 MHz or so are absorbed by the atmosphere, and would require a very long antenna anyway.
This leaves a frequency range of between 10 MHz and 300 GHz or so. To be usable for communications, there has to be a
carrier signal at some specific frequency band. (It would be a single frequency only if it was AM modulated, but that's a terribly inefficient way.) To be inside something that can be digested, the antenna elements cannot be too long (although they don't need to be straight, somewhat reducing their size), so the most likely range is between 1 GHz and 10 GHz.
We can take a look at
frequencies used in RF id tags. So, to simplify matters a bit, we can probably safely say that you might have ingested some kind of RF ID tag or active transmitter.
(The dust spec-sized terahertz band ID tags demonstrated by MIT, TFID, has almost no range, because atmosphere itself absorbs that frequency quite well.)
Note that not all transmitters need to be active (with their own battery): the same antenna can be used to receive power, and there are even backscatter techniques where nothing is transmitted by the device itself, as its antenna just modulates the received radiation.
So, this simplifies the problem of how can one find a hidden, unknown type RFID tag. Most RFID detectors are dedicated for a specific type (a specific frequency range), so those are out. Security services do have sensitive wide-band EM detectors to look for surveillance devices, so something like that would be my bet.
Although some describe me as the paranoid type, I know nothing about these, but a quick online search finds shops dedicated for this kind of "spy tech", with typical ranges being 1 MHz to 8 GHz (8000 MHz), for a fraction of the sum you offered –– but of course I have no idea whether they actually do what they advertise. I do believe private investigators use some of this stuff on behalf of their clients, so that is an approach that might help.
To eliminate external sources, you want to do the measurement inside a
Faraday cage. The easiest way to achieve that with minimal resources is, uh, kitchen alu foil. No, not a hat: just make a large cardboard or paper box (with e.g. wooden supports), and paper over it with the alu foil. The foil is conductive (although the very surface layer contains an oxide that is nonconductive), and "blocks" most frequencies of the electromagnetic spectrum. (There are limitations because the foil is so thin.) Even a chicken wire cage works at longer wavelengths. The rebar and meshes in concrete work in a similar way, and is the reason one often has bad reception in large buildings, unless they have repeaters inside.
I also cannot help but point out that it is rather common today for us humans to have problems that generate symptoms like belief in allergies related to electromagnetic radiation or electricity, paranoia and other similar fears, because we simply haven't evolved to live in the situations we live in and with the utterly overwhelming communications methods we're constantly bombarded with.
I cannot stress how important it is to react to those symptoms –– and indeed treat them as symptoms of an underlying problem, instead of as a separate, purely physical problem –– and get help. I personally recommend therapy, and consider it as something that is intended not to remove a problem, but to make you strong and resilient enough to deal with it. So, to me, a therapist is not someone spouting psychological mumbo-jumbo, but a personal trainer that just happens to be specialised on the mind instead of the body. The difference to physical therapy after an injury or illness is neglible, in my opinion.
I myself have burned out repeatedly, and because I did not seek help to fix the underlying problem, I now suffer from recurring depression, and am completely unable to deal with stress. I used to
thrive under pressure, now I just collapse like a deflated balloon. Things used to be even worse –– much, much worse –– just a few years ago; mental training (in my case, via cognitive-behavioural psychotherapy) has really helped me build myself back together. But, because I let things completely crash, a decade after my last burnout, I
still have a long way to go before I can fully take advantage of my existing skills, and can only hobble along, verbose Uncle Bumblefuck fashion.
Now, if I can be this direct and honest with somebody who
statistically is likely to be a troll or attention-seeker, whoever is reading this post is surely capable of considering themselves and their own ailments in the same fashion. The particular problem at hand might be psychological, psychosocial (being manipulated by the "friend" into believing things that are not real), or physical (having ingested a real RF ID transmitter or similar gadget). It is
important to consider all three, and not exclude one just because you
believe. This is the cost, definition, and benefit, of being rational.