Hurt a fair bit for the first couple of days then gradually get better over a few weeks (assuming it works). It depends exactly what's being injected, and why.Small risk of infection, small risk of local effects (skin thinning/colour change).Because it's a variant on a female steroid, you may find your moobs get a bit bigger, but it's usually a small price to pay.
If it's just a subacromial injection, see above. Although, you'll have no trouble with moobs but your cock will shrivel up.
Eh? Dennis the Dodger, Rodger the Menace and that shit?