I'm skinny, can you help?

[iWantGetBig iGoinGetBig]

I'm 17, soon to turn 18. My height's between 6'0 & 6'1. My scale says I weigh some 150 pounds, but I can't really believe it so let's say I'm in the 140 range.

Long story short, I'm really pinner. I eat as much if not more than a lot of my big friends, and I've tried this year to work out. But I'm really not seeing any improvement. I'd never really been particularly skinny until Grade 10 and even though I'm a late bloomer it just seems abnormal to be this skinny.

Can anybody give me any suggestions for exercises I can do build mass? My upper body and lower body both need work, but my arms are really my priority, I'm starting to get pretty self-conscious about them.

Just so you know, I'd cut some muscles in my left hand & fractured my left arm in 2 accidents earlier this summer so my left arm is really behind my right arm in terms of strength.

Thanks for any advice

 

[Typhon]

You can't build mass through exercise alone, get your diet sorted first as your body can't build muscle without adequate resources. If you're a 'late bloomer' with puberty it's probable that your body is still burning calories like crazy. That doesn't mean you can't gain weight though.
A little trick that worked well for me was upping the amount of liquid calories I consumed. I drink 2 litres of milkshakes a day which adds about 1,400 Kcals on top of the usual solid foods I would eat.
Try using a website like fitday.com to track calorie intake and shoot for at least 4,000 a day. You should gain on that, if you don't, go up to 5,000