Braxton hicks And kegels? 24w pregnant

Kylee • Pregnant with my 4th, lost the 3 previous angels. Due oct 2015
So I was doing my kegels yesterday for pretty much the first time, I know I should do them everyday. Anyways my belly started to tighten really tight like a basketball and then releasing happened a few times. Then again at home relaxing on my back and then later on my side. Freaked me out I didn't know that's what braxton hicks were. Called dr and he said not to worry, unless in a patern and more often. 
What I'm asking is when did u ladies get them...and what was it like...and how often....and have any of u get them after u do your kegels? 
Thanks ladies