Inflammatory perhaps, and seems so,

but piriformis stretches away will hardly, rarely, solve the issue.

So many times I see Knee to chest stretch, knee crossover stretch given over and over over weeks. Never, or rarely actually solves the problem as this stretch (especially done without supervision) does not get to the root of the issue.

The more likely issue is that there is some form of related mis-alignment issue that is causing the piriformis to tighten, and perhaps the glutes (abductors) in a manner that causes the issue to return repetitively.

The ideal would be to look at alignment and strengthen the piriformis in a position that improves lower limb, hip alignment (in relation to other daily activities said individual performs). Gluteal work is a must in these situations.

Regards