There isn't sufficient information to give you a specific diagnosis. It is possible that you may have fractured a rib. I would advise you to visit the orthopedician so that you can be examined and undergo investigations such as X-Ray chest, Ct/MRI(if indicated), etc so that the underlying cause can be found and treated accordingly.
Next Steps
Follow the steps as advised
Health Tips
If condition persists or worsens visit the ER at the earliest