I am on Baclofen for part of my Pain Management and it is really a drug that would or imo should not usually be prescribed for acute pain it is actually for ongoing pain and used to treat MS and other nerve or neurological pain. I too am in the area of needing to loose over 100 pounds and am unable to excercise due to chronic pain let alone walk much more than around the apartment and use a power chair. Have you considered bariatric weight loss surgery? I just went to the beginnings of mine and it was a seminar and there is alot to it but it can now be done laproscopically and may be the key to losing the 150pounds and ending or easing the pain in your back it may be something to speak to your doctor about. Hope you get to feeling as well as can be expected. Take Care, kk101