Lump On The Arm, Shoulder Pain With Numbing In Hand. No Injury. What Is The Reason?
Thanks for posting your query.
The lump of on your left arm needs to be clinically evaluated for it's diagnosis as it can be anything from a minor lipoma, or cyst or a neuroma to a soft tissue or bony tumour either benign or malignant.
From your symptoms, the pain and tingling are sugesstive of a neuropathy which might be due to nerve compression by the mass or growth on your arm.
You should consult your like xrays and ultrasound may be carried out before confirming the diagnosis and starting appropriate treatment.
You can get baseline blood tests like blood counts, vit B 12, ESR, etc done under the guidance of your PCP and depending upon the results he might refer you to either neurosurgeon (nerve related)or orthopaedic surgeon (bone related) or oncosurgeon (tumour).
Please do not neglect your symptoms as even though minor lipoma or fibroma or any inflammatory condition are more likely at your age but it's better to be safe than sorry.
Hope I have answered your query. Please accept my answer in case you have no follow up queries.
Regards,