I do not mean to sound harsh but if the Arthritis is only in your thumbs at the moment you are fortunate, sadly it is likely to get worse, and may eventually effect other joints. It seems to me rather early to be offering injections if the pain is only recent, usually in the early stages it is more to do with "managing". You need to be aware of triggers, too much of anything may aggravate the joints such as PC/mouse, typing, phone use, gardening, chopping etc., Hand/wrist supports can help when doing certain tasks, painkillers on the days when its really bad as unfortunately Arthritis flair ups are common.