<s>[INST] I have a lump on my right collarbone, about half way between my shoulder and my neck. It's an oval shape and is just over two centimeters in diameter. It feels like its filled with fluid, almost like a bubble and is sore to touch. Should I be worried or is it some sort of buildup of toxins that will go away by itself? [/INST] It is most likely a Sebaceous cyst. You can get it removed by a small operation if it is bothering you. Nothing dangerous otherwise. Take care. </s>