For some excersizes i get tired to the point where i cant do another rep, but i dont feel "the burn" in my muscles...should i try and find a new excerise to work these muscles.
Short answer: No.
Long answer: Not if you keep progressing.
Longer answer: Progression is more important than feeling a "burn." Even if you stall out, that is you cannot progress for a few weeks, you may be able to continue progressing with that exercise by varying the parameters (sets/reps, rest time, grip, dumbbell to barbell .. etc.)
Good answer, goochadamg.
OP, you could also try loading heavier weight.