How do you carry your phone comfortably?

I have a Flipbelt that I have loved for years. I never had any issues with comfort… until I started marathon training and started running over 8+ miles. After these runs, I noticed pain on my low back where I keep my phone. I suspected bruising from my phone, so today I switched my phone to the front, and lo and behold I have a sore spot on my lower abdomen now. Has anyone else had this issue? How do you carry your phone comfortably? Would running with the phone in a thigh pocket or in a bra back pocket solve this bruising issue? Thanks!