Hi, About 3 months ago i noticed a small red, ball like lump on my left hand side, just below my ribs. This lump has now got a little bigger, from its original 2mm to about 5mm in size, its also getting darker and turning a slight purplish colour and has started to hurt. It is hard and smooth and feels like a little marble and sticks out about 3 maybe 4mm. What could this be?