Hi!
It all depends on the size and location of nodule. Most nodules in the region where you have lymph nodes (neck, armpit, groin etc) are swollen lymph nodes. They are enlarged due to infection, inflammation or cancer. Subcutaneous (below the skin) nodules in torso or arms and legs are usually not cancerous. However, yes, some can be skin cancer. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.