Loop through the Controls array and find each checkbox - that's trivial:
foreach (Control c in Controls)
{
if (c is CheckBox cb)
{
...
}
}
Then your only problem is finding the relevant label though all the checkboxes I am aware of have their own Text property and don't require a separate label. If you must use a separate Label control, then I'd use the Tag property of teh CheckBox control to refer to the relevant Label and get it that way.
Then all you need to do is convert the string based number to a numeric value (I'd suggest the various TryParse methods) and add 'em.