What Could Cause Sudden Pain In The Left Shoulder And Heart Palpitation?

So I’ve had a split spleen before grade 4. And for years I had pain in my left shoulder blade that never went a way. After awhile it did. But This might sound strange last night my heart was a racing and I thought maybe a panic attack as I was trying to fall asleep. It scared me because I was afraid I wasn’t going to wake up so I took half of my Xanax as needed. And just a minute ago I took a big sip of water and I felt a dull ache in my left shoulder when I did! What could be cause that ?