If you had doctors eliminate any structural issues, it could just be that the inactivity allows scar tissue and fascia to lock down.
Check out this video: http://www.aimsportsmedicine.com/the_fuzz.html
*guy is goofy but its great information
I had serious medical issues that did not allow me to train for around 2-3 years. I was a competitive athlete and had super active professions where working out was required my entire life prior to this nightmare. After those 2-3 years, every old injury I forgot about in years past, as well my back, hips and legs were in severe chronic pain. It took a few years of regular deep tissue/ART, "stretch to win"+PNF, lots of foam rolling, yoga, meditation to relax body tension, etc to get back to some sort of quality of life. Regular insurance just wanted to allow me loads of pain meds, muscle relaxers, and sleep meds. But that only makes your health worse and does not solve any problems.
If you can find someone skilled in ART type deep tissue work, might give you some relief. As well foam rolling and stretching on a daily basis. Might sound wimpy to some guys on here but yoga can really help rehab and pain management often times too.