I am running my Pi as a plex server with 2 Hdd mounted. There are good days and bad days, my Pi will just freeze up and I cannot reset it. I have tried putting in a new memory card, checking the overclocking(which is non existent) and nothing seems to help. I feel as though it overheats frequently as well. Any Suggestions. I am new to pi and am not sure how to troubleshoot next.
Check/replace your power supply. I'm not sure if either of your 2 HDD are USB-powered, but that certainly would increase power draw from the Pi and cause freezes if your power supply was not fully up to the power draw.
Each USB port can draw 500mA and the Pi itself draws ~500mA (depending on which Pi you have), so with two USB devices you'd want at least a 1.8A power supply. If you have a Pi3, the Pi foundation even recommends 2.5A.
Certainly possible there is other stuff going on, but 9 times out of 10 when I've had Pi freezing problems, swapping out the power supply with a higher quality and/or higher amp power supply has solved the problem.