The knots under your left shoulder blade could be because of muscle spasm due to any heavy activity you were involved (lifting heavy-weighted things, muscle sprain
, etc.). Massage
the affected area, apply warm clothing, and take pain killers.
If this is not your case, you can do an ultrasound
of the knot to clearly understand its origin.
Feeling light headed is related to having low blood sugar
. You should eat often and in small quantities, do not let yourself become hungry.
I believe your hot flashes and rapid pulse happens at least 1 hour after eating, and is related to reactive hypoglycemia
You can check with your GP what is the cause of hypoglycemia in your body to get proper treatment.