I had surgery for trigger thumb 3 months ago. now my thumb is swelling and stiff. this just started one week ago?

Get it looked at: You should be well over you're trigger thumb surgery @ 3 months. New swelling , pain and stiffness may be indicate a new problem w/ your thumb ( arthritis of the base of the thumb is very common ), tendinitis , infection or other malady. See your orthopedist for evaluation . Best of luck.

Overuse?: Did you use your thumb heavily last week? If you have been protecting it as you heal, and now you're using it more normally, the swelling may be normal for 6 months after surgery. If normal use continues to cause swelling and stiffness, see your surgeon. Be very careful to not overprotect your thumb! too little use allows swelling and stiffness. 2 minutes of exercise every 30 min really helps.