I have pain on the inner side knee joint. i think i injured the cartilage the pain was bad when i hurt it but now about a week later i'm still feeling a dull ache on that same spot. can cartilage heal on its own? i have full movement of the joint?

Knee pain : To understand knee pain a doctor has to examine the knee in person. Pain bending the knee can come from internal problems in the cartilage, ligaments, or bones. Inflammation from the knee cap rubbing the leg bone. Knee cartilage damage often can improve with physical therapy or may require surgery

You should have an in-person visit with your primary care doctor or an orthopedist to have this issue properly diagnosed. They then can refer you for any testing, such as X-ray or MRI, if needed, and for physical therapy if necessary. This could be injury to cartilage, or bone, or bruising, or partial tear of a ligament.