I was taking Lexapro (escitalopram) for two years after the death of my son I have now stopped taking this I weaned off slowly I now have headaches is this normal?

No. If you had migraine headaches or even tension headaches that were relieved on lexapro, (escitalopram) this could be the case for a time. If the taper was slow, and over a considerable period of time - weeks to months, this would be unusual. Restarting the Lexapro (escitalopram) would be of interest to see if the headcaches resolve. On the other hand, did you feel that you effectively grieved his death? Ssri's can "numb" one.
Possibly. You should have weaned off of Lexapro (escitalopram) for 2-4 weeks. If it was shorter, you may experience headaches and palpitations for up to a week or two.