Can tight pirifirmis cause referred pain? can the pain be tender or would it be excruciating pain?

Yes, piriformis syndrome can cause "peripheral sciatica" secondary to compression of sciatica nerve as it passes out of the lumbosacral cistern. This usually is unilateral and can be detected on exam by stretch maneuvers. An EMG/ NCS can readily localize and demonstrate extent of problem

Tight periformis causes referred pain in hip, back, and groin. Tenderness deep in the buttock with pressure to the periformis is classic, but hard to self diagnose because the proper examination is performed laying on your belly. See a musculoskeletal physician to choose the right treatment. You should heal well.