This sounds a lot like a ganglion cyst. Ganglion cysts are fluid filled growths that originate from the connective tissue that surrounds the tendons in the wrist and hand. They are totally benign, meaning they do not indicate an underlying medical problem and they do not turn into cancer.
Because of this many ganglion cysts do not need treatment if they are not painful. In fact, some will spontaneously go away over time if you wait long enough. However, a significant number of ganglion cysts do continue to grow or become symptomatic in other ways, for example they can be painful from bumping them constantly or because they catch up on your tendons when you try to move your wrist.
If you have these symptoms (and it sounds like you do) then your best bet is to talk to an orthopedic doctor
(your primary care doctor
can refer you). Sometimes, cysts can be reduced in size by removing the fluid from them with a needle. However, many cysts do require surgical removal. This is a relatively minor surgery
, however the main complication is that there is a relatively high rate of the cyst growing back even after the surgery has been done.