I get mine badly when I sleep or lay around with my hip flexors in full extension.

I have just had major Knee surgery so this week is killing me , I combat it by lying flat but with my legs elevated at the knee so i have a good bend in the hip.

Or I sleep sitting up, I get the same results. On my side I’m fine but while I am stuck in a Full brace i just have to sick it up.

Sorry I’m not more helpful

(There are also great videos on Flossing the nerve with stretches but you have to persevere with those and do them multiple times a day to get relief but they work.)