Pain in lower part of chest when jumping/running

[nbal15]

I started working out again after a long break, mainly doing push ups and jump rope every single day. I tried looking up what the proper form is for both of these, made videos of myself and it seemed to be fine. About a week ago, I noticed that while jumping or running, the lower middle part of my chest has a bit of a stinging pain that mostly appears when I’m moving in an up-down motion and gets stronger the more I do so. It doesn’t happen at all when I’m doing my push ups or relaxing. It’s definitely not my heart or an organ, the pain isn’t coming from deep within and it’s not that high up either. Do you guys have any ideas? I tried to stop doing my jump rope routine for 3 days but it didn’t help.
I appreciate the help.