loud squeal every now and then when making phone call

[bigcarm15]

has any one had this problem every once and a while when i try to call of recive a call my phone just makes this loud squeal noise that is unbarring . i can still here the person talking but i hear the squeal as well . in order to stop this i had to shut phone down and pull battery for 20 min then it went away .. can anyone help with this is it a soft wear problem or a phone issue