Since a lot of your pain is in that thumb joint, another possibility is bone spurs....which often accompanies arthritis. I had that surgically repaired a year and 1/2 ago and have never looked back!!! (They remove a small bone at the base of your thumb and fill that space with tendon from your forearm...no more bone on bone...no more pain.)
Please talk to your doc about it. He/she is the one that can diagnose you properly. We all want you to get the best possible relief!!!!
Patti