Are these danger signs?

1. Feeling a sharpish pain in the muscle you are working out with. Not enough pain to adversely affect form but it is noticible.

2. Not feeling tired at all but not being able to put out near as many reps as you are normally able too.

3. You work out for a while and you get a bit tipsy from tiredness without feeling muscle fatigue.

4. Shoulders are mildly irritated and inflamed

( Doesn't adversely affect my form in shoulder exersizes but it is uncomfortable and annoying.)

Should I stop when I feel these things? How dangerous would it be to continue working out if any of these signs are present.

Also, I'm a 15 year old male ( Skinny, but in good shape) and I'm about 5 feet 9 inches