So about 9 to 11 months ago I started feeling a dull ache in my upper mid back on the right

It goes away with rest
It comes back with any kind of exhursion. Even lifting a gallon of milk with my right hand or going for a 3 mile walk makes my mid upper back ache on the right side

I've tried PT, I've tried Tylenol, I've tried ibuprofen gel, heat, cold, menthol strips

The only thing that makes it go away is rest. I took a month off doing almost nothing except maybe walking and even then I could still sort of feel something wasn't right back there. Not that there was pain, but it didn't feel right

Anyone have any idea what to do about this or has gone through something like this?