Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine you and obtain a history, I can not tell you what the exact cause of your symptoms is. However I will try to provide you with some useful information.
If there is a bruise ( meaning change in color of your skin where you were hit) or a bump where you were hit, it is bound to hurt for a few days. If you don't have any other symptoms with it, like headaches, change in your hearing or vision, ringing in your ears, loss of consciousness etc, you don't have to see you doctor. It should probably resolve over time. If it persists for more then 10 days or so, or you develop other symptoms you should probably get it checked.
But if you were not hit that hard, and it's just pain when you push down on it, it should probably be ok.
I hope this helps.
Good Luck!