I was up late last night researching this, so I will pass it on:
Burning is caused by lactic acid during workouts. It can go away fast or in 2 hours. Soreness is caused by micro muscle tears. You typically feel it withing 12-24 hours. You know you will do some growing if you are sore and take nurse yourself afterwards. You will probably build muscle much slower if you don't get sore at all. There is disagreement about the optimal amount of soreness, but a day or two of soreness is considered OK for growth by people on both sides. Some are sore for a week, though I think that is dumb. Some people say it is OK to do cardio while sore. I disagree. Very lite, high rep movements that don't come close to a burn should give more blood to the sore muscles.
Reps: force = mass x acceleration. High force = strength, and higher reps = endurance, but if you do 5 very slow reps, that is like 15 faster reps, and if you lift 50 pounds, that is like lifting 25 pounds with twice the acceleration. So the number of reps is ambigous unless you always lift as fast as you can, though this is not necessary for max results. But note that when you lift fast and gradually slow down, you are gradually reducing the amount of force you are using, which burns out the fast twict muscles first, and then uses up some of the slow twich as well at the end for a better burn. For this reason, if I pick a weight I can lift in less than a second, but take at least half a second to lift, even though I can lift a lot more, I can start out fast twich and have the effect of reducing the weight as I go. But lifting a heavier weight through a longer rep is more intense, so a mix is good. While lower shorter bursts are better for growth, anything under 30 reps or especially under 20 will still get results with less risk, so the main thing is to lift some weight and not sit around thinking about it too hard.