Hello, I'm a 16 year old male. For the past couple weeks I've been having these stabbing pains located to the left of my chest above my heart. It accurs at least two times a day and only lasts at most ten minutes. the pain hasn't spread anywhere else. It only accurs when I breathe deeply (the pain intensifies when i breath deeper) or move in a different position (leaning back, laying down, sometimes just walking) if I breathe hard enough I get this popping feeling in the same area and the pain immediately goes away. This isn't my main concern, I looked up what it could be and most arnt life threatening. What I'm mostly worried about if it ties into the things that have been accruing the past couple days. About two days ago I've been having black, tarry stool that smells very foul. That night I had this very painful stinging pain to the left of my lower abdomen that only lasted half a minute. The next day I had more black stool that smelled even more foul, with weird feelings to the bottom sides of my belly. The feeling is a very small pinching/stinging that last a couple minutes and happens a lot of the time during the day with also a lot of bubbling in my stomach, it can be heard and felt. I've been burping up a lot of acid during the period of these couple days. The heart pains still accur. As of today it's the same as the last but I'm very fatigued/tired even with ten hours of sleep, I can barley read without a haze covering my vision. The pains in my belly are slightly more painful, just slightly, but I once felt it cramp up a little bit on one side, it only lasted a couple seconds but hurt more than the pinching feeling. I havnt eaten or drink anything unusual in the past week. I don't consume alcohol either. I havnt been taking iron supplements nor ingested pepto bismol. I know it may be a little early to be worried but I am. Thank you for reading.