Things you can try.
-Dilute your gear with a sterile oil.
-Heat the gear to about 80 f before shooting (lowers viscosity of oil and allows for quicker dispertion of the chemical so you have less irritating substance concentrated in one area, this is especially common with Winny in an aqueous solution).
-Inject in the morning, injecting and then lying still for 8 hours while your asleep doesn't help soreness. I know from exprience Im very lazy and hate injections so I wait til about 11pm then grudgingly do it and then Im sore as hell the next day.
-Massage the area thoroughly after you inject to speed the dispertion.
-Ben Gay, or Horse linament (found in a tack shop, its used on show horses) will increase blood flow to the area, again speeding dispertion of oil and drug.
-If all else fails... PM me and you can donate it to the hype to the Excalibur foundation, im sure they can use it.