The reason is that muscles can't bear heavy pressure. . . Another important reason is insufficient warm-up before exercise.

It looks like you just have a muscle fiber injury there. First of all, you should ice your muscles and gently move them to prevent them from hardening. Stick on anti-inflammatory cloth, rest for 2~3 days, and apply hot compress. It should be ready in a week!

You can gradually resume exercise after you feel no pain. . . .

Stretching and warming up are necessary before and after any exercise! !