It seems like whenever my phone is on it is overheating where the SD card and the SIM card is located. It doesn't matter if the phone is turned off or if it is on. I tried the safety removal of the SD card and turning it completely off and I also deleted older pictures and some music and it still overheats! What do I do?
I would try all of the above first, but keep in the back of your mind..Samsung had some Motherboard issues with various models and it does cause them to get extremely hot.
If that is the case or none of the above things work for you, Samsung can check it, switch out the motherboard for less than $75. I can't remember the exact cost. I talked to Samsung last year about the price for an S3 needing a new motherboard and it was something like $70.80.
I had to do this with my Note 3. It had 3 motherboards in that phone, the one when I got it, I sent it in for overheating, they replaced the motherboard, it went bad in a few minutes, replaced it again that same day and I never had another problem.
I didn't try all of the above things first because my phone was under warranty and just a few weeks old. Had it been older and no warranty, I would have tried the above suggestions before sending it to Samsung.