A punch in the side can make it hurt badly.
What Make Your Side Hurt Really Bad?
It could be wen you drink any liquid o you eat any ting and run after your sides hurt.
If this is a medical question as it is categorized then your right side hurting badly could be your gallbladder or liver. Your right side maybe your pancreas but it can also just be a pulled muscle. I suggest a doctor if pain persists.