Alright, I'm wanting to become a pilot but I've had multiple back surgeries as well as had my left knee replaced and I'm only 33, but I'm current getting back to normal and just got off the pain meds. My question is can I get a first class medical? I can doing anything anyone else can do except touch my toes or take off running. Thoughts???

FAA medical is not an astronaut or military physical, plenty of folks with significant disabilities flying airliners.

It will be OK to have limited ROM, most folks can figure out how to work the controls with significant impairment.

That said, what you'll probably need...

The condition(s) will need to be fairly stable, ie they need to be confidant that you won't be suddenly disabled on the job because a disc slipped or something.

Probably no significant pain... you're the best one to judge that. I have a very high tolerance for pain, so would probably not even report minor nuisance aches and pain if it's not a distraction. That's your call.

Off pain meds. Addiction will be a no-go, and any history that even hints at addiction will likely require extensive and costly evaluations.