I recently found about a 1 cm lump on my left side towards the middle-to-bottom part of my rib cage. It is very hard, mobile and painless but since i discovered it, it has gotten bigger and seems to be growing. Although the lump itself is painless, the whole side of my ribcage seems to be tender, and I often have an on-and-off pain all over my ribc age from time to time. I have been very fatigued lately with less and less energy every day, it seems.
I went to the doctor and she said to keep a close eye on it to see if it gets bigger. Is this just in my imagination or should I get a second opinion? Is it not a big deal? Please, I'm very concerned because lately I have been doing some research online on different diseases that may have to do with the lump and Ewings sarcoma, a bone cancer, seems to be the one that fits what I'm feeling the best. I have already ruled out a sebaceous cyst, so I know it's not a cyst or anything. Please help!