I get sharp pain on the left side of my ribcage just below my cleavage for about 15 seconds when i sneeze or cough. should i be concerned?

Usually not: If the pain goes away quickly on its own and no other symptoms are present, would not be worried. Most likely inflammation of the cartilage in the rib cage (medical name costochronditis), Due to old trauma, a violent sneeze, lifting something heavy for example, arthritis in the area, viral infections, fungal infection, very rarely cancer. Try motrin/advil for a couple months, IF persistent, see MD