I have a lump under one arm stinging me very much hands, feet, calves and abdomen , interrupting my sleep. Also I just noticed a lump under my arm - I am a man of 47 years and sometimes I feel so much more - Should I be worried?

I will try to answer this question with the limited information I have available. You definitely need to seek medical attention. There are many possibilities with general symptoms such as itching or pruritus. It could be scabies, eczema, dermatitis, liver disorders or polycythemia. Patients with more stinging feel itch overnight. It is a condition caused by the mite Sarcoptes scabiei. It is contagious. Scratching more in the shower with hot water, most likely have polycythemia, a condition in which the number of red blood cells in your blood is high. If you have any of these conditions or not is difficult to determine, but please make an appointment with a licensed doctor in your area to get a definitive answer. I hope the answer helped you.