Yes. An exam and diagnostics would give a definitive diagnosis and appropriate treatment, if warranted.
A lump on the skin of the ear could be due to a traumatic injury, skin parasite, yeast or bacterial infection, or dermal mass.
Cocker Spaniel's often get ear infections. Ear infections can be itchy and or painful. If your dog has an ear infection she could scratch her ears which could cause a lump due to the scratching. This is one possibility.