LTSpice is limited in that sense. You have a strange, largely undocumented feature for placing voltage labels on nets.
Remove all .STEP directives from the circuit. The feature works with fixed element values only.
Select DC operating point (.OP) analysis.
Click right on the background, then select
View->Show .op Data Flags
Turn the checkbox on for that item.
Run the simulation. Only after you ran the simulation once you can perform the next step.
Right click on the background, then select
View->Place .op Data Label
Move the label to a net. Once dropped at a net, it should display the DC operating point value of that net.
You can right-click on such a label and select another value to be displayed, or construct an expression, e.g. rounding the value to two significant digits. As long as the label is attached to a node the $ symbol in an expression refers to that node.
Once dropped at a net, you can move the label away from the net with the move tool (the hand). The display should then turn to
. You can then right-click on the label and select a value to be displayed.
It is all rather convoluted, not to say brain dead. It maybe only makes sense when preparing a schematic for some educational presentation.
It is
SO much easier than this.
Draw schematic.
Run transient analysis.
CLOSE the graph window.
Click on any node (wire) and it will label it with a voltage. Repeat as desired.
Run transient analysis again whenever you change the circuit.
The key is to close the graph window, since with that open, clicking on a node (wire) adds it to the graph rather than labeling it with the voltage.
With the graph window open (either run transient analysis or menu item "visible traces" to open it):
To add voltages to the graph window, click the wire/node. To add currents, ALT-click a wire, or (generally) click a component or leg of a component (such as transistors). You can also ALT-click a component to get the power dissipation of the component... this is useful to check safe operating area of power transistors for example. All these are graphed as instantaneous values in a transient analysis. You can also get the RMS, average, and/or integrated values (as appropriate) of those by CTL-clicking the label of each waveform in the graph window.
(p.s.the above is all applicable only to LTSpice).