Sculpting problem

Hello, i have a little problem with sculpting, when im using the grab brush and i want to sculpt a character from the side, i want to clamp the cursor to the centre of the y axis in the model, so when i grab im grabbing the whole head, not a tip near the centre of it

Of course you’re grabbing the whole head, look how big the tool radius is.

that was the solution, big radius, i accidentaly made the radious big when i took the capture, thank you