This may be your first child and the anxiety in you is obvious. While feeding the child please make the area of feeding comfortable also you should be mentally relaxed and hahibg any kind of mental stress. Don't think os stopping the feeding as that's the only nutrition what your baby is getting. Mother's milk is a boon for the child.
Next Steps
Please concentrate on the child while feeding do not do anything else while feeding. Check if you have proper milk flow as I'd milk is less child will tend to suck hard or bite with the gums of course as one does not have teeth at such young age.
Health Tips
Just apply Ice if the area is sore intermittently for 5 minutes after feeding and Take Tab Dolo 650mg twice for two days. If this does not help seek proper medical help from your Pediatrician.