What icauses buttock pain radiated to thigh?

A pinched nerve: A pinched nerve or compressed nerve root (l3/4 is possible). Alternatively, msucle spasm and pain from facet joints can cause similar pain.

Pyriformis v disc : This can occur due to a disc herniation in the lower back and not cause any back pain or be due to a hip muscle known aa the pyriformis irritating the sciatic nerve which it straddles in the buttock region mimicking a disc herniation pattern. It can be hip bursitis or arthritis, a sacroiliac joint problem or degenerative changes in the spine referring pain to this region.