Linda, I can see why you are stumped.
How long has this pain been consistent?  Could it be that the 2 yr old has
changed some of his BF habits a bit?  A little more tongue play, or tongue
games while BF?  Mine did that and boy was I SORE.  It took some real
detective work and some careful atching of his cheeks and jaws to figure it
out.  I mean, heck my nips are tender 'cause I am pregnant, but there was too
much soreness going on, so I looked for and found other causes, and fixed
them.  We can now BF virtually painfree!  (Thank goodness!)

I wish this mom the best!

Jay