I feel pain in my chest and the side of my heart too to the back (rib).... it happens almost every month and sometimes twice or thrice in a month ?

19 years old: At your age, heart disease is so rare as to be discounted. The more likely cause is musculo-skeletal: costochondritis, myofascial syndrome, rib contusion, fibromyalgia - to name a few. You list Panadol (acetaminophen) - does it help? If so, that about nails it. If not, try an anti-inflammatory like ibuprofen or naproxen. Heat, massage, & good sleep also help.