What to do if i broke my 3rd and 4th metacarpal and still have pain in my hand?

Not enough info: How long ago were the fractures incurred? Were you treated? Please provide clarification and re-ask.

Depends: This depends on what type of fracture and how long ago the fracture had occurred. Also if you have already had treatment and are still in pain> If you have had treatment and still in pain have you had formal hand therapy. More information would be useful to help guide proper treatment options.

How old ?: Even if the fractures were reduced and set properly you should anticipate 4 months of reactive swelling, and intermittent pain for up to 8-12 months. Therapy may be very helpful to obtain maximal range of motion and pain relief.