My site used to go down constantly. Had problems for months. I had to modify a file to fix it temporarily for a few days. Support couldn't help me. I tried to receive a refund so I could switch provider but they said no. I ended up making a whole new website in hope that would fix the problem but nope. Still the same big. So I contacted support again and they finally told me it was the new BLUEHOST plugin that was causing problems for many people. I just had to deactivate it.
I hate bluehost.