My back, twisted and curved spine, 2 lower disc's are bad, plus I have Arthritis in my lower back, so I can relate to the Pain thing.
I stopped playing about 12 yrs ago, after playing for about 6 yrs. And like you, my first time at the range was, well, lets just say, it wasn't pretty..lol Then I joined this great site, and was offer some sound advise. After a few sessions at range, I could see some improvement. If you go to the practice Range forums you'll see some great advice, I followed it, then went for a lesson with Mike and he greatly improved my swing, that was about 5 months ago, and to this day I still work on the basics, I can now hit balls with some degree of consistency, so hang in there.
oh, and the pain is still there after hitting son many balls, but I still come back for more lol
So, check out the site for tips, ect...