There's a trigger point on the inside of the thigh that contributes to "weak knee syndrome," says masseur Rich Phaigh. That trigger point is responsible for a lot of generalized pain on the inside of the knee, too.
To get rid of that pain, move your hand straight up from the kneecap along the front of the thigh for about 3 inches, then move it inward for another 2 to 4 inches. With the tip of your thumb, press in firmly and hold until you feel the muscle release its tension. That can be anywhere from 30 to 90 seconds, Phaigh says. Then release.