Benign Sebaceous Cyst: A common, harmless lump under the skin, often appearing near the ear. It can become slightly tender if infected or inflamed, which aligns with the recent appearance and slight tenderness described.

Acne or Pimple: Given the location and description, it could be a large pimple or acne lesion, especially if it's new and slightly tender.
Furuncle or Boil: An infection of the hair follicle, which can appear as a small, tender lump and could be located near the ear.
Epidermoid Cyst: Similar to a sebaceous cyst but typically filled with a cheesy material, it can also appear as a small, sometimes tender lump.
Lymph Node: Enlarged lymph nodes can feel like lumps and can be tender, especially if there's an infection or inflammation in the area.

Parotid Gland Tumor: Although less common, a lump near the ear could be related to the parotid gland. Tumors here can be benign or malignant, making early diagnosis crucial.
Metastatic Cancer: In rare cases, a lump near the ear could be a metastasis from another cancer. This would be particularly concerning in individuals with a history of cancer.
Infected or Inflamed Salivary Gland: Conditions like parotitis can cause swelling and tenderness near the ear and jaw, which might be mistaken for a lump.

Branchial Cleft Cyst: A congenital anomaly that can appear as a lump near the ear, typically along the anterior border of the sternocleidomastoid muscle.
Pilomatrixoma: A rare, benign tumor of the skin, often appearing as a firm, mobile nodule, which could potentially be located near the ear.
Neurofibroma: A benign tumor of the nerve tissue, which can appear as a lump under the skin. It's more common in individuals with neurofibromatosis but can occur sporadically.