Hello, I have just registered looking for advice this summer to finally get in shape. I have never participated in basically any physical activities over the years besides gym classes.

I weigh between 120-125lbs, which is basically water weight and I can lose it daily. I have never really followed a planned routine or diet to try to gain muscles. I think I am what would be considered a "hard-gainer" as I read on something like Yahoo questions or something, where it said it will take you like 2x as hard to build muscle because of a fast metabolism and you aren't turning fat to muscle.

I have basically no fat whatsoever, possibly like 2-4%, I am so skinny that I have a full six pack without ever attempting to get it. My legs are fairly toned from basic running and required stuff we had to do in gym, the only thing lacking is my bicep/tricep area and chest.

I can do about 20-25 pushups in a row till exhaustion, in which I'll have to take a few minute break. I have never benched anything before in my life, but I can lift about maybe a 40-45 with my right hand and possibly a 30 with my left. My left arm is considerably weaker than my left.

Is there any possible routines/diets you guys can point me in that will help me increase the power of my left arm to where it matches my left, so I can efficiently get bigger?

Any help will be appreciated, thank you.