Hello,
Thanks for posting your query.
A hard immobile pea size lump on the mastoid process is sometimes a prominent mastoid process itself. Just check if you have this swelling present on the other side too.
If the swelling is unilateral then most likely it is a swollen lymph node which can happen due to minor infections in the head and neck region.
A pea size swollen lymph node is not significant and usually subsides on its own after the infection subsides.
You need to self monitor the swelling for any pain, tenderness, increase in size or fever. In case these symptoms appear, I encourage you to consult your physician for proper examination and further related investigations.
Hope this answers your query. I will be glad to answer the follow up queries that you have.
Please accept my answer in case you do not have further queries.
Wishing you good health.
Regards.

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Hello.

Thanks for writing again.

The unilateral lump behind the ear is more likely a lymph node only. Other possibilities may be a sebaceous cyst or a lipoma. But, without a proper physical examination, it is very difficult to mention whether it is normal or abnormal.

In any case, it is not likely to be associated with your feeling of being out of your body.

Let me assure you this is not something life threatening condition.

Hope my answer is helpful. Please accept my answer in case you do not have further queries.

Wishing you a trouble free speedy recovery.

Regards.

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