If you are skinny and have always been skinny with a very low body-fat no matter what you eat then you need to combine your hard training with correct eating if you want to add muscle to your frame. It simply cannot be done by doing exercises to failure once or twice a week.
It needs a plan and a system to increase your overall core strength and power that you have. It is with a strategic plan that you will increase your lean body mass and not by some accident that you happen to get stronger. It is all about strength because the stronger you are the bigger your muscles will get.
Training with correct form at all times you should start off doing sets of 6 to 12 reps if you have not been training for more than a year. If you have been training for more than a year then using sets of 5 with only 5 reps is recommended for fast strength gains. The rest between sets that you take is going to decrease as you start to get fitter.
These hard workouts should ONLY be trained a three times a week. Deadlifts, squats, military press, bench-press, wide grip chin-ups and barbell rows. These are your basic compound movements designed to increase your core strength so that you are able to increase the weight that you lift every week.
Hard and intense training are going to be completely useless if you do not eat correctly as your muscles will be desperately trying to repair themselves from the minute you walk out the gym to the minute you get back to the gym, if you train three times week. This means your macro-nutrients that your body needs to do this repair must always be available.
Firstly you need extra calories because of the extra energy used as well the extra calories needed to help repair the muscle damage that you have done with your hard training. Although everyone is different if you are a skinny guy then you should eat 20 times your bodyweight counted in calories.
What this means is that if you are a 131 pound skinny guy who does not have much muscle then you are going to need to eat 2 620 calories per day which is 131 X 20. Although everybody is different this is a good basic to start with. If you are not seeing results and you are training hard then you should try and increase your calories to 23 or 22 times your bodyweight.
The 3000 odd calories that you are eating every day needs to come in regular intervals, which means that you need to eat more than just three times a day. Try and eat at least six times a day, which is something that can only be done by planning your meals ahead of time and not resorting to impulse buying when your sugar gets too low.
Your basic macro-nutrients are going to come from complex carbs and protein with about 10% or 15% of your food coming from good quality fat. If you do not know where you can find these foods then you should spend a little time online and learn about what is the difference between good protein and bad protein.
Eating and hamburger and fries every day because you can without getting fat is not the answer to your problems as this will only result in over-training when your muscles are not able to repair in time for your next workout. You need to make sure that you are eating good quality foods if you really want to add some good quality muscle to your body.