Hi, I have even seen people who have tooth ache or abdominal pain when having a heart attack. So, yours is not strange at all. People would always think that the heart is on the left side of the rib cage, so it would always cause left side pain. Emm. Not always. There are just many supernatural things that just do not make any sense. Of course, there are "correct and official" explanations for this. The nerves that control the heart, in some people, may also control other areas. So your brain would sometimes mistake the signal transmitted from your heart as something that is transmitted from other places (in your case, right side rib cage).