When i get an erection usually my urethra (or frenulum, they are so close) hurts. i cant remember if it started before or after stretching
anyway i also just looked and there is a small circle patch slighty redder than normal on my glans (it kinda looks like a layer of skin is missing on that circle too, in the light, but it might actually be raised?
anyway, is it yeast?

You can determine if it is by treating for yeast. If it goes away, it is.

hmm well it appears to be all gone now, i never used anything... ill worry if it comes back i suppose

General purpose soothing agent.

It would be extremely unusual to get pain on erection on its own account since you have - and always have had - frequent and prolonged erections during the night which compel the foreskin to stretch to match whether or not it retracts in doing so.

You certainly may experience some discomfort from stretching, and the abovementioned cream will cope with most consequences.