Needle injections
Dukhalon is correct. Also, novocaine, xylocaine or any 'caine that is injected to numb an area burns like a wasp bite. What is uncomfortable (in addition to the blood vessel with nerve wrapped around it and vein alonside) is the volumn of liquid that displaces tissues and puts pressure on the nerve. Having said all that, some injections are just plain painful. Gamma Gobulin tends to make you limp for awhile. Some need to be mixed with other drugs or something called Neut in order to neutralize the acid/base of the injectate. But the bottom line is this, do it fast, avoid areas known to us to be sensitive and move on. Life is hard sometimes we just have to knuckle up. And for years now we have been able to apply painless topical numbing agents before injecting tender young folks.