Get coordinates points between x and y - c# winforms

Question

I have a jpeg image in a picturebox, on page load i am drawing the rectangle based on the x(150) and y(440) coordinates. now when i mousemove on the picturebox i need to identify the rectangle by their coordinates and highlight the image. for example see the below image ..

lets take the first rectangle, on mouse move any points inside the rectangle i need to perform some actions.. how to find the coordinates between these x and y for the rectangle?..

suggest me any ideas

Thanks

Dev