Synerel changes your hormone level, and you will find that this change is what is causing the headaches. Once you hormone level stabilises, they should subside. You may find that when you start jabbing that you get them again for the same reason.
Syneral puts you in a state like menopause - hence the hot flushes, drynesss, etc.

as for pain relief no ibprofen or nurofen type drugs. But anything paracetamol based are fine. Obviously use as weak as you can, but if it gets hard core you can use Myersondol or even panedine forte- as long as they are paracetamol or codedine based

also when you start injecting your next stage, try giving the injections late at night, and that way any changes that will occur, will happen overnight, and lesses the effects you feel during the day.

HTH and good luck!!!
odette