"By the way working out doesn’t help me. I have gained no weight from working out and actually lost weight."
This is supposed to happen - when you start working out with the intention to gain weight, you end up losing several pounds first, then you start to regain it.
Eat healthy (less than 25% of your calories coming from fat a day, get all of the needed vitamins/nutrients/etc. you need), exercise, and get enough calories so you have energy to exercise and live (1800~2200 is probably best.) If you have a fast metabolism, you could probably eat more calories and not gain weight.
Eating whatever just for the sake of gaining weight is a terrible thing to do, mainly because you start overloading yourself on what you shouldn't be eating (mainly fats). If you're going to eat for the sake of eating, at least eat healthy (oatmeal, fruits and vegetables, etc.)
