Are people injecting into thighs?

I started PIO yesterday and forgot how awful the pain is. Last time I was on PIO for about 3 weeks before finding out it failed. We rotated injecting into the upper buttocks/hip section and by the end of the three weeks I was in quite a bit of pain.

My clinic says to rotate injecting into the buttocks and thigh but notes that the thigh is very painful… I never see anyone on these threads mentioning injecting into thigh, and the pain comment makes me feel nervous.