I notice that whenever I try to do any yoga postures with my right leg moving across my body that I get a sharp pain in my right hip. When this happens, it feels like the hip is bumping up against something and can't go any further. What could be causing this?

The description you are providing sounds like a possible impingement syndrome. Impingement means something is getting pinched or compressed.

In the hip, that something is usually some part of the soft tissue anatomy. It could be a tendon but most likely it's the rim of cartilage around the hip socket.

Combining hip flexion, internal rotation, and adduction (movement across the body) presses the femoral neck junction against the superior labrum. If this motion causes pain, it is a sign of femoroacetabular impingement (FAI).

The labrum, a dense fibrocartilage ring that is attached to the hip socket may be torn. This ring gives the hip socket depth at stability. It has nerve endings that set up a painful response when it is impinged.

The first step is to see your doctor. A positive FAI test is usually followed by further evaluation of the hip. X-rays, MRIs, or even arthroscopic exam may be needed.