How can I lose wt. with so much pain and health problems?

I think you should consult your doctor before going on any form of diet.  Between your medication and your existing conditions there are a lot of things to consider.  You will need to find a diet that will encourage

Losing weight and keeping it off is a lifestyle change, not a temporary diet. If you are looking to make the change, I'd suggest reading a great article called Lifestyle Changes, Not Diets, Are Key To Losing Weight that was published on Medical News Today. I think it really sums up the important aspects that most people need to change to successfully lose weight and keep it off. The three points I spend extra time focusing on are portion control, drinking lots of water and making exercise a part of my daily routine (even if it means taking the stairs instead of the elevator or parking my car further from the entrance of a store/restaurant).

I hope this helps.