I have a LOT of heel pain and i can share what I do. If the pain id under the foot, close to the arch then it may be heel spurs or fallen arch, a foot doctor can tell you more. I found a good article that I think explains it better.
Most of my heel pain is in the area that surrounds the heel, where lots of people get dry cracked skin, it is around the heel, not the bottom. My doctor told me that it's because I have always worn shoes with heels and my tendons and ligaments are shorter than then need to be so when I wear flater shoes it stretches those tendons and ligaments out and they get inflamed and painful. Cold soaks and massage really help the pain. Also anti-inflammatory meds help reduce the pain. Better that Tylenol, which only treats pain, not inflammation.
So, when I buy shoes of any kind I have to choose a shoe that has more heel to it, I cannot wear shoes completely flat. Lots of newer styles of athletic shoes have a more of a heel than just flat. I'm not saying a High Heel, just the heel is a bit higher than the ball of the foot.
I went to physical therapy for a month, 5 days a week. The best thing to help my foot pain was the stretches they taught me. Standing on a step,if no steps then a thick book, with the heels hanging off. Pushing down, stretching the heels out gently. Picking up marbles with my toes. Putting one foot back in a lunge tyoe stance and pushing that back foot down. Here's a link to show some and explain them better than I can.
Really good pictures here.