I have a big problem, my combat level is 57 and I just got level 25 att,def and str. And the problem is that i dont get anymore exp by killing creatures, or anything. Pls help me out!
Since the Evolution of Combat update, there is a separate interface for choosing what skill to gain combat experience in. When you are in game, click on the combat interface panel by clicking on the crossed swords icon.
If you click the circular button labeled "XP", there will be an interface that lets you choose what skill(s) to gain experience for melee combat, ranged combat, and magic combat (note that you always gain constitution experience regardless of your choice).
Note that choosing "Attack, Strength & Defence" does not increase the experience you gain, it just splits the experience between the three skills.
After RuneScape 3 update, click on the three bluish orbs icon, then choose whichever kind of exp you want.