It shouldn't sting at all. Basically you are just injecting water with a little bit of BA. No peptide, hcg, or gh should sting. Sometimes after you may get a little itching or redness around inject site but not stinging while it's being injected.
That happens with igf reconned with AA.
As far as keeping Human Chorionic Gonadotropin (HCG) out of the fridge it will lose potency rapidly. If not refrigerated it's not worth having because it will lose potency before you can use it.