Im in a similar boat-
Although sum ppl will disagree i definately think u should be getting into weight training.
Im no expert at all but i have learned shit loads from
www.bodybuilding.com
excellent site
Calories are important yes, bu that doesnt mean stuffing down macca's al the time, either though they have great calories (sum ppl do this).
Your body is basically an ectomorphus- where the people who can eat wat they want and (while where young) wonder where it went.
I'd recommneded starting weight training- mon/wed/fri
about an hour on those days with compound movements- benching/squats eg-
split it up and definately do not over train
Currently i do-
Mon- chest/shoulders/tricepts
Wed- Back/Abs/Biceps/Foreamrs
Fri- Legs
Its up to u, but the best gains and muscle development will have to come through weights. If you just eat ull only put on fat.
U want to be adding to ur calorie intake each week
id recommend going on a hard weight gainer and protein shake- ull need these especialy post work out and before bed.
Keep up some cardio as well but not dramatically, save the energy for the gym.
Consume protein roughly 20-30 g every 2-3 hrs!!!
Some fatty acids- tuna is a great source are good.
You'll need complex carbs as well- multi-grain bread, wheatbix... and many protein shakes contain them
Octane rebound is great.
Drink 3-4 litres of water a day. Space it out though. Dont forget ur skinny so u can treat ur self still to some junk food just dont live off it.
They say its nearly 80 % diet when ur being and 15% rest- Yes u must allow rest- this is when ur muscles grow.
Once u get serius u might want to look into creatine as well- its a safe and great supplement which can lead to massive gains.
Anyhow id recommend seeing a professional fitness/helth store dude and of course a local GP before starting any of this.
Good luck i hope i havent told u anythin wrong im sure sum 1 will disagree wit me-
check out that website for heaps of info- just dont get confused- i use to overloaded with conflicting information and confuse my self
anyways good luck and have fun seeing those muscles grow- ive recently lost the visibility of my rib cage! lol and ive never been happier.