I have not encountered a phenomenon such as this with a nipple sensitivity and weight association. If it is psychological, it is conceivable that you could eliminate it with weight loss. This would be in your favor from a health standpoint anyway so what do you have to lose? OK, weight - and pain....
If this does not do the trick, perhaps seeing a therapist would be a good place to start. Your doctor might be able to come up with an idea as well. Hormonal changes (estrogen and progesterone) can result in breast sensitivity and you could be approaching perimenopause. These are things to discuss with your doctor.
Chances are this is nothing to worry about except for how it interferes with your comfort.
The answers in online forums are for information only and are not intended to substitute for medical advice and care. Please see your personal health care provider for further evaluation of your individual case.
Debbie Miller, RN