any idea why this might be? i have a strength of 37 and im at level 24 but each time i level up i can't increase melee combat at all (it's stuck at 10).

If i remember correctly u need to have certain lvl of strangth to lvl up melee combat.

Melee combat is a skill, so, to increase it, you should spend the skill points you gained through your experience. It is distinct, numerically, from strength and general level. Progressively, you'll need anytime more skill points to increase a skill of 1 level. From level 1 to 4, you'll need 1 points, from level 5 to 9 you'll need 2 points, from level 10 to 14 you'll need 3 points, from level 15 to 20, 4 points.
At any rates, it depends from your character class: if you are a thief or a priest, 10 is the level cap for this skill.

yep. guess that's it then