help with winny shots

i need help with my shots i use 21 gauge needle and it keeps getting pluged up any advice.

Do you shake the contents of the winny before you draw and inject??

Pain

always shake before drawing last time there was a little blockge when i shot it in and last night i only got half in and the needle stoped dead couldn't budge it even drew back a little and pushed again . i read about guys useing 23g and not have probs.. i am stumped

what is the dosage of the winny.....im guessing that its 100mg/ml...i used zambons last spring which are 50mgs and i used a 25g pin adn had no problem...also what kind of winny are u shooting