Right knee pain when bending to sit & bending to stand back up. No pain whilei sit, stand, walk ect. Exercise helps but 4 days+no exercise=pain. Why?

Patella. You may have a patella tracking issue. As the patella slides in between the femoral condyles, if it is misalgined, it can cause pain as it glides incorrectly through that groove. Physical therapy for quad strengthening specific to the side that is weak in your quad can help a great deal. The tighter your quads become from no exercise, the more the pain, which is why your have noticed that.