What could cause my snakes bones to pop and crack?

Iv had my red tail boa for nine moths and sincd I bought her she has never been active or a good eater, she used to be freindly at least but not anymore, in the past few months I've noticed her bones we're petuding on her sides in a few places. I took her to a reptile expert he suggested she was just doing it herself because they seemed to go away when she changed positions, now she is bony every where and when she bends her bones pop and crackle like popping nuckles., I used to just feel it but now I they are audible, if I give her body a slighr pul and bend I can feel be bones poping all the way down, this seems to give her more mobility. She doesn't seem to bend normaly or have much control until I assist her in popping. I took her to the leasding reptile vet in the area and he didn't know what to tell me, we did blood test but they we're unconclusive. If there is any known parasite or bactereal cause for this than I will order a fecal anaylasis but or other test but I want to know if that's the right test before I do it because its expensive and i m not to atatched to the snake that's done nothing but bite me and waste food since I got her, but I understand that if she's sick its my responibility to help her, her temps and humidity are normal and to my surprise she has eaten the rats I got her last week and the week before, iv never seen her drink but I ensure she always has clean water to drink, body inclusion disease has not been confermed or ruled out the blood test annalis person said "maybe I'm not sure, it looks like it could be but might not be early stages "