my 3 year old son has been complaining of pain in his lower sides and sometimes lower back and it is always after he drinks something. it has happened less than 5 times, but all in the last month. it almost doubles him over and he says his "side hurts from drinking too much" (usually chocolate milk, but once with water.) does this sound familiar? what could it be? i am going to take him to the doctor asap (i had an appointment, but cancelled because i thought it went away), but i am curious as to whether or not this was a common problem relating to a specific problem.