Muscle soreness coming back

Muscles would not get sore after crash about 2.75 years ago. If I tried to do weight training I would get very agitated, severe insomnia and brainfog for a day or two, no muscle soreness whatsoever so I avoid sports and weight training. Yesterday, I decided to do some pushups. Today I actually felt sore in my chest like I used to and didn’t get any negative symptoms. Nothing changed in my life except I have been actually doing less cardio and I’ve been trying to ingest more probiotics but who knows if that’s doing anything.

Anyone else have muscle soreness disappear and then come back? Hoping if I take it slow I could start building some muscle again.