depends what type of juice ure using...... Human grade, UG Lab, ect... some shit leaves u sore some don't... some oils leave u sore some don't.... some have to much BA, some don't... some people wiggle the needle inside their body during injection and taper muscle fibers, some don't, some heat up their vials to make the oil more smooth, some dont, some bake their vials to kill off BA, some don't, sum rub out their inject area after darting themselves, sum don't.
different things can cause and/or relieve soreness, ya diggit?
i use EO oils w/ low based BA, my shit never is sore until I whip up a batch and shoot 300mgs of 3 different compounds. in 1ml.. that shit leaves me limpin