Furthermore ....

1) Shorts which have tight elastic on the leg bands can also cause Vastus lateralis pain (that's a quad on the outside of your thigh) down near the knee. It's the same sort of thing as the medial knee pain I described above, only it feels like there is a very painful bruise about the size of your fist in a spot roughly where the leg band of your shorts is located. You can identify the shorts as the problem by lifting the leg band off the painful spot while you are riding. If you feel some relief immediately ... that's the problem.

2) As for tight shorts increasing circulation ... you've got the right idea there, but the wrong piece of equipment. Sugical stockings will increase circulation and are recommended for patients who have to spend a great deal of time in bed or not moving around much due to an illness or injury. They are also recommended for people who take long flights to various parts of the world, where you not be able to move around for extended periods of time. I have no idea how these stockings work. However the difference between these stockings and a pair of cycling shorts is that the stockings don't have a tight elastic band located somewhere about mid-thigh. They are usually all one piece from toe to hip. It's the elastic leg band on the shorts that can create the opposite effect of what you are going for.