Im sorry to hear about your symptoms. Now a sensation of fluttering in this area has to eb first considered for heart problems. The first one which comes to mind is that you could have a condition known as arrhythmias . These are irregular heart beats in the area which can cause the fluttering sensations, palpitations, chest pain, shortness of breath, dizziness, lightheadedness, sweating etc. This would be diagnosed on a simple EKG and a 24 hour holter monitor test. Sensations can radiate back into the area of the armpit as well. once diagnosed they can be treated easily with medications.
Now apart from this it is possible that these fluttering sensations are due to muscle fasiculations or spasms which are occuring in the area. This can be due to a number of underlying issues and in most cases they are benign. This can be due to caffeine intake, alcohol intake, dehydration, electrolyte imbalances. A simple blood test to look for electrolyte abnormalities can diagnose the cause. In addition increasing your water intake and also drinking electrolyte rich fluids would be beneficial. Cut back on caffeine and see if that helps.
Now if this was an artery you would have pulsating sensations, as you have stated which in most cases can be a normal response to stressful stimuli and due to changes in blood pressure. In most cases, nothing needs to be done.
I would think this is likely to be due to muscle issues, try using the above remedies and see if that helps. if you have additional symptoms which i listed initially then you need to have the arrhythmias ruled out. Also if this is an artery then it can be picked up on a simple examination. try the remedies and if it doesnt improve, see your doctor for a full evaluation.
Do you have any more questions?
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