I've had up to 8 vacutainers taken at one test, and no problem, no light-head, or anything. I have a BIG appetite for breakfast, so I go for bloodwork early in the morning and eat immediately after. As far as if it hurts; no more than any other kind of blood test. It's only 1 needle, at least on all the tests I've had.
Muscle tissue biopsy: DIFFERENT STORY! That needle (I mean tent spike) hurts.
On the fasting, you will get all bad results if you were told to fast, and you didn't. It's a BIG issue! Whatever the test instructions say, do yourself a favor and go with it. And tell the truth when the lab tech asks exactly what/when you last ate. No coffee in the morning, and ask if you can take any meds you're on, or if you need to wait. I'm giving this tough answer because I screwed up once, and had to pay the $1200 all over again after the tests came back all SNAFU'd!
Charles