Unless you're one of the lucky ones that isn't effected, Propionate is just going to hurt. Warming the oil before injecting might help a little but it won't neutralize the pain from Propionate.
If the spot is still sore or swollen from the last injection, you should avoid injecting there until those symptoms subside. There are 4 pairs of common injections sites you could be rotating for a total of 8 sites. Ventro-gluteal, gluteal, quads, and delts. Since you're injecting EOD, you might choose to skip quads as in my experience they are definitely the most painful out of all those spots. When I inject Prop into my quads I won't be doing legs for a while so if you do choose to pin there you might want to plan your training around it.
Even with 6 spots you'd only need to hit each spot every 12 days or so which should give you plenty of time to recover.