Hey guys and girls, I'm a new member so be nice and help me out!

I'm a twenty year old male in college at USC, working out hard for the first time really in my life. I started last year when I got to school, and quickly went from about 150 lbs to 175 lbs. I'm a little over 6 feet tall.

Anyway, I've been working out for a year since then, and I haven't gained very much weight at all (though I've been getting a lot stronger), even though I've been throwing back protein shakes like they're going out of style. Besides that, my main problem is that despite the rest of my body looking pretty muscular and strong, my chest refuses to develop at all.

My routine doesn't have a particular order, but I try to do all of these things when I go to the gym (which is about 4 times a week).

_______
Cardio:
30 Minutes of jogging with intermittent sprinting
3 Sets on bicep curls machine (130 lbs)

Machines:
3 Sets of 8 inclined chest press (130 lbs)
3 Sets of 15 chest flys (175 lbs)
3 Sets of 10 inclined shoulder press (140 lbs)
3 Sets of 10 tricep push-downs (150 lbs)
3 Sets of 10 deltoid flys (100 lbs)
3 Sets of 15 leg extensions (175 lbs)
3 Sets of 15 leg press (325 lbs)
3 Sets of 25 calf extensions (250 lbs)
2 Sets of 50 crunches (with added 130 lbs)
2 Sets of 12 back extensions (200 lbs)
3 Sets of 12 seated row (150 lbs)

Free Weights (dumbbells only):
3 Sets of 30 bicep curls (each arm) (30 lbs)
3 Sets of 15 chest flys, laying down (20 lbs each arm)
3 Sets of 10 bench press (35 lbs each arm)
3 Sets of 15 forearm curls/extensions (20 lbs)

Other:
3 Sets of 10 pull-ups
3 Sets of 30 classic push-ups
3 Sets of 20 triangle push-ups
3 Sets of 50 crunches
3 Sets of 50 bicycle-crunches
_______

Well, the rest of my body is looking pretty cut, but my chest is the same scrawny one I had sophomore year of high-school.
I feel like I do 'chest' workouts with my arms, and I have no idea how to change it. Maybe I'm doing them wrong, maybe not enough weight, maybe the wrong workout in general.

Any advice/tips will be greatly appreciated.

that routine is crap,to many exercises to many sets to many reps.
try a fullbody workout using mostly compounds m,w,f,
squat/deadlift alternated
bench-press
chins
milltary-press
dips
bent-over-rows
that is enough add bis and tris if you want.

How long have you been doing this setup?

university of Southern California or University of South Carolina?

that routine has way to many sets and way to much conc try more compounds less machines I still think that machines ruin some good compounds personally, also whats your diet like because most of how much you gain will come from that you should be eating a wellbalanced 6 meals aday
heres what my routine looks like for chest/back and shoulders and mines not even perfect but im gettin great results!!!
shrugs, deadlifts, pull ups, front/lateral raises, bench/military press, bentover rows, planks (core and lower back at the same time yah buddy) 3 sets each (total 40min, 2 days a week) not in that order though id always do deadlifts when your fresh planks last

To the questions, about 6 months, and Southern Cal.

Next, I do lots of machine because I had a pretty horrendous broken arm 2 years ago, which makes bench-press and some other lifts pretty much impossible (my bone strains, which is incredibly painful).

Anyway, I eat about 4 times a day, whatever I can get (I'm a college student!). I don't eat fast-food or junk food often, and I rarely drink. I do throw back 100g of protein in the form of shakes or bars every day as well.

I'm not looking to be a body builder, just build another 10 lbs and build my chest up. I'm getting the feeling that I've been going about this wrong, so what kind of routine do you recommend? Remember, some free-weights are hard for me because of the arm-break.

Thanks!