I converted to an epilator from wax about 2 years ago- you can get rid of much shorter hair so no waiting for a bush of regrowth, and i actually found it less painful as i was in control of how fast or how much i did. Much easier to stop half way for a break than waxing!
If i do it regularly, it hurts much less- found a week is how long to get visible regrowth, at a push could leave it 10 days before it needs doing. As opposed to every 3 days shaving.
My top tips to minimise discomfort.
Always have a hot bath or shower first to soften the follicles. If you really cant, then soak a flannel in rather hot water and apply to your underarms, then dry them thoroughly and start.
Also, take a pain killer 30-45 mins before you begin, if you have a low pain threshhold, you could get some topical analgesic ( i.e something you rub on)and put it on first
good luck