Does changing the concentration of a solution also change its pH?

I'm really confused, i know that pH is the measure of the H+ ions in a solution, but how does pH relate to molarity exactly? And how does changing the concentration affect the pH?Does changing the concentration of a solution also change its pH?
Only if you change the concentration of [H] since pH = -log [H] so when you increase the amount of [H] in a solution, the acidity rises cause the pH to lower.