Sounds like you're royally fucked up.
It doesn't matter WHAT you do, anything is better than what you're doing right now, buddy.
Start eating small meals throughout the day.
Start lifting, you'll see improvements.
And you're gonna be sore when you workout, it's called DOMS, beginners get it bad. (Delayed onset Muscle Soreness).
I barely ever feel it anymore.
And the whole hard-gainer thing is bullshit. Some people have a harder time putting on mass when they're not 100% dialed in. I know I get the same way sometime.
But when I pay my dues, when I eat right, I gain quickly enough.
Get to the gym, start eating.
Stop being a pussy and you'll thank yourself for the rest of your life.
I don't mean to sound like a dick, but this is stuff you've gotta hear man.