MacBook Pro CPU spiking, runs slow and fan is loud

Hi, i've got an Early-2011 13-inch MacBook Pro. 4 Gigs of RAM, 2.3 GHz Intel Core i5 Processor.

I was running Yosemite when the problem started, currently on Lion but the issue persists.

The problem started about 2 and a half weeks ago, when I would turn it on the fan would slowly get louder and the trackpad/mouse movement would lag. I checked Activity Monitor to see if anything large was running, but I had only two programs running (Chrome and Activity Monitor) that accounted for maybe 3-5% of the CPU usage. Still, it said that over 80-90% of the CPU was being used.

When I start up the computer in safe mode (which takes about 6-10 minutes) the slowness is mostly gone, but I could still hear the fan running way more than usual.

I tried fixing the permissions, and i've tried verifying and repairing the hard drive. The hard drive was corrupted, so I used an external device to repair it and the job appeared to be successful. Putting the HD back into the computer, the problem still persists. After that, I wiped the HD (after creating a Time Machine backup) and restarted everything with OSX Lion. The noise and slowness still haven't gone away.

Can anyone help?