Normally I focus on the tactile sensations on my upper lip when doing meditation. I tend to feel tactile sensations of the breath there. But when I try to stay one pointed on one specific sensation on one spot, it tends to disappear, and another sensation appears somewhere else, making it harder for me to concentrate on that spot. Or when I try to focus on that sensation, other sensations around the desired area of focus tend to pop up and distract me from focusing on my object, thus ruining my focus.

Should I just force my focus there?

This is really confusing for me. Please help.
Thanks