A simple overuse to major injuries of musculoskeletal system can cause such pains. Needs more detailed history and evaluation.
If it's acute, temporarily cold application and topical pain ointments or sparys will help.
But suggest a good medical consult to get rid of it at the earliest.
Get well soon.
it may be due to sudden jerk or heavy weighlifting, please provide some proper history if any present, and use wrist support while exercising,
also can use analgesic like ibuprofen if severe pain occuring