Thank you for your question. A lump close to your ear, near your jaw may be arise from the following structures:
1. Parotid gland - The parotid gland is the largest salivary gland and it lies just in front of and under your ear. Hence, a growth (tumour) from this gland may present with a lump or node in front of the ear or at the angle of your jaw. Fortunately, 80% of parotid gland tumours are benign and the most common parotid gland tumour is pleomorphic adenoma.
2. Lymph nodes - Lymph nodes are part of your immune system and are present throughout your body. Your neck region has numerous lymph nodes and can be big when you have an infection in the head and neck region.
An reactive or infected lymph node may be large and tender initially but usually subsides or reduce in size when the source of the infection is treated. Lymph nodes can also be big due to the spread of a tumour in a nearby organ.
3. Skin and underlying fat - There can be many growths on the skin or its underlying fat, ranging from cysts to lipoma (benign tumour of the fat)
4. Muscles and bone - Although much rarer than the above mentioned causes, benign and cancerous growths can arise from the muscle (e.g. leiomyoma, sarcoma) and bone (e.g. ameloblastoma).
Without a complete clinical history and physical examination of your lump, it is not possible to advise you on the likely cause. I would suggest that you visit an ENT Specialist for an assessment of your lump.
Hope this helps and all the best!