I have oa which is very painful in my fingers with heberdens nodules. I cannot grip even light weights anymore. What kind of resistance ex. Should I do?

Arthritis. Arthritis in some form is a common cause and OA is the most common. The bumps on the distal joints near the nails are called heberden's nodes and the ones near the pip or middle joints, bouchard's nodes. Warm water helps to ease stiffness, and full gentle ROM is better than resistance. Cold is good AFTER activity if there is pain. Daily FULL gentle ROM, a good goal, decreased pain gives strength.
MULTIDISCIPLINARY. It sounds like you are frustrated and uncomfortable. Try going to an occupational therapist. They will give you exercises and other treatments that can help with pain and function. Depending on your overall health and medications that you take, it may be appropriate to try a topical or pill-based nsaid. There are other pain medications that may be appropriate for you. Discuss with your doc.