What makes the injection of short estered steroids more painfull than long estered ones? Ie: Test suspension > Test Prop > Test E. I would guess the short esters are more irritating, if so, why?

Why is it that winstrol , a water based mixture, free of pain entirely upon injection (from my experience), but sore hours and even days later. Is it because the winstrol is still in crystal form, and if so, why?

Just some ?s running through my mind...