Hie, My name is G.D. I am 68.8 kgs, 158 cms height, female. I weighed about 84 kgs about in August 2013. I have lost weight with the help of a certified dietitian and constant walking, running, yoga and cycling. I walk 5 kms and run 700 meters comfortably without panting heavily. Today I felt a prick sensation in the left side of my chest towards the end of the jog??? What could be the posible reason? Also I want to prepare for the marathon next year...dream run(6 kms)...Is it okay??