Sir as per your complaint it might be because of dequervain's tenosynovitis occur due to repetitive thumb movement very common. It's better if you are using splint and resting thumb. You should visit a near by qualified physiotherapist that will assess you further and treat you. If it is the same problem as a told he will give you ultrasonic therapy and as the pain get better some eccentric exercise for thumb and wrist. Wish for your good health soon. Thanks for posting