Hello Victoria and welcome
It seems that your have heart palpitations if I was not wrong. These type of palpitations can cause headache and arm ache. The causes for palpitations are:
1. Anxiety or stress
2. Atrial Fibrillation
4. Valvular Disease
In my opinion consult your cardiologist and get your EKG done at the time of episode or get your holter examination done.
If it is not palpitations than it might be Gastritis
. Take some analgesic
to reduce pain.