I think you have to talk to as many people as you can about this pain point. They should not be friends or family. They need to be at best acquaintances. You want honest feedback from people who don't care about hurting your feelings, only what they need for their business.

How big of a pain is it? Does your idea solve that for them? How much would they pay for your service over what they use now? Can you make switching cost effective? ....