What Causes Painful Lump And Swelling On Knee Cap After An Injury?

Earlier today I fell with all my weight on to a rock and landed straight my knee. The pain was horrible, it immediately caused a lump and some swelling on my kneecap. Although I am able to walk it has been aching all day and feels almost tight-like and hurts especially when twisting, bending or flexing straight. Felt silly going to the doctor since I am able to walk, but wondering now if I should go and what could be wrong