Hello and thank you for using HCM.I carefully read your question and I understand your concern.You shoud not worry, its nothing serious.
My opinion as a cardiologyst is that this is nkt a heart pain.A typical heart pain is not related whith eating or drinking. An ischemic heart pain usaly is retrosternal..like heaviness,squeezing, it might irradiate to the arms, it least for 5 to 20 minutes.It is not like a nidle poking and of course it is not related whith eating proces.
An apple juice can not cause a heart pain.
It might be a digestive problem.A
gastritis may cause an epigastric ,pain..irradiating toward the heart, like burning,poking.
The apple juice might aggravate a gastric problem.Or it might be just a random pain becouse you have eaten a lot.Sometimes a stomac distention gives this kind of discomfort.
So my opinion is that you have e nothing to worry about your heart.Keep monitoring this discomfort avoiding tha apple juice for a litle time and see what happens.
Whish I was helpful.Take good care.Best regards.