Don't warm up before playing, and don't start playing games immediately after warming up. You can pull a high ball with your friends first.

Your condition now belongs to soft tissue contusion. You can go to a regular hospital to do a Chinese medicine physical therapy massage, and the price is not expensive, tens of yuan at a time. And try not to use your injured arm too hard at ordinary times. Apply it with a hot towel every night, and then gently press the wound with your hand to relieve the pain. This kind of soft injury generally does not fall on the root of the disease. Just raise more.

If you don't want to go to the hospital, I suggest you buy a topical medicine "Futaling Ointment" (as if these three words are there) and go to the pharmacy to know. The effect is good, especially for soft tissue contusion and strain.