Hello and welcome,
From your presentation, we need to establish a few things before we could help you. Was there any trauma to the hand suffered the day the pain appeared?
Or was there an increase in physical activity? These could sometimes trigger pain in an anatomical region which is otherwise used to physical activity.
There could also have been an incident during which some nerve damage
could have occurred (direct trauma). This will also settle on its own, but will take time.
My advice would be to consult your family physician for an examination and detailed history discussion to rule out the cause for the pain, and avoid the same in the future.
For now, you could avoid lifting heavy objects with the same hand and try to reduce the work load during the day. Sleep on your other side so less weight is applied to the effected arm.
Mild pain killers would be the best option as we don't want to damage your kidneys with strong drugs.
Wishing you the best of the health.