Photoshop - eraser and lasso tools creating random vertical lines on mouse button release

PLEASE can someone help me with an issue I am unable to solve by resetting the tools for my eraser and lasso as both are acting incredibly oddly and when I use them on an area, on release of my mouse button a straight line spikes out diagonally almost to the edge of the artwork page. It is erasing or selecting depending on the tool an area I have not asked to be selected!!