Sharp knee pain when sitting for long periods of time like in a car around kneecap and sometimes in the back feels really tight same if i go run onit?

Anterior knee pain. : I think you may have weak quad muscle putting increased load on knee cap resulting in pain. Other option is knee cap injury with cartilage damage and pain. You are very young for arthritis. If symptoms persists you may need to see orthopedist for more formal exam.

Knee pain: This can be caused by patellofemoral syndrome (also called runner's knee), which occurs due to a problem with the knee cap. It is worsened by squatting and kneeling, so those activities should be avoided. Search "patellofemoral syndrome exercises" on the Internet search engine for videos of exercises that might help. A knee support that holds the knee cap in place may also decrease pain.