It probably won't do you any good, but don't make a habit of it and it shouldn't do any harm either. You only recover and grow while resting, and working out again before you have recovered is not a sustainable practice. Many athletes will always do that but then take longer periods of rest after a time of accumulating fatigue by working out "too much", but for amateur/hobbyist lifters I really don't recommend it.
Do different lifts tonight. If you're super trendy and squat/deadlift then thay will do.
if you ache after a work out, that means that you tore muscle and you need to rest to build the muscle again. however if you do not ache, im sure you can go for another work out. try not to stress your muscles, and perhaps focus on cardio as well.
You shouldn't work out the same muscle groups more than once every 48 hours. Work on legs (e.g. squats, leg press, etc.) if you're going tonight: they're the most important muscles to work if you want to gain serious muscle, and neglecting them will make it harder for you to gain upper body mass. Phaggot
Everyone knows that the more you lift the bigger and stronger you get. This is essentially without limit, so ideally you would train your whole body as hard as possible every day of the week, every week. You'll progress two to three times as fast as someone who only lifts a few times each week.
As long as you're training different muscle groups your fine. I do chest and biceps on Mondays and Back and Legs on Tuesdays.
I wouldn't do that, your biceps are unlikely to have completely recovered by the next day, neither are your triceps from the bench press. If you are going to do 2 days back to back i would do chest and triceps and biceps and back unless you are fairly advanced and your muscles can recover that quickly
I do chest and biceps monday but shoulders and forearm the next
Just so you know, when you get here it will never look like that. Ever
To the OP; if you eat right it's fine with the sort of stuff you're doing you can recover quickly on a good diet with enough sleep at your age. Also squat more. Much more