Sciatica

That was my guess, too.

It happened to me a few times too. I was told that it is due to the lack of exercise.

you've got a condition, best to get medical about it, see a doc

If you are standing, there is a good chance you have the wrong type of shoes.

Aw mate, this started happening to me a few times now randomly since I hit my 30's. Waking up in the morning with a pulled muscle, in bed, for absolutely no reason. I think it's just called getting old and your body degenerating, Wah! :( Was the foot up my ass I needed to get a PT though!

Probably not the muscle, but one of the tiny filaments of connective tissue that attaches to the muscle. Feels pretty much the same, but it can be caused from holding the same position for too long (standing or sitting) and then once you move you feel the tightness/ stretching. I'm guessing that you stand or sit without a lot of movement for long periods of time. Just try to move around every 30 minutes or so. Look up some light stretches that you can do while on the job, that should help keep things from locking up.

Wrong. I'm too hyper to stand/sit still for very long.

What if OP has a standing job, like the post seems to imply? Does he has to ask for a sitting desk? Seriously, see a doctor. 90% of the comments recommend it.

I work in a pet store. Can't do desk work. Too boring.

I just thought this would give others a laugh. I would talk to my doctor, but my insurance doesn't cover the doctor I've seen most of my life.

Thanks for sharing, it was slightly amusing :) Yes, it's an unfortunate reminder of ageing! I can't believe you need insurance to ask a doctor about your butt health though! Thankfully, our butt health is free here!

Yeah. Too bad I'm only 28. I'm not old enough for this shit.