Hello dear,
1. The lumps in the armpit are enlarged
lymph nodes.
Usually they are indicative of infection & your Doctor had prescribed antibiotics suspecting the same.
But as they have not subsided, it will be better to get a
biopsy done.
2. The pin & needle sensation in the arm is attributed to the compression of nerves in the armpit by the enlarged lymph nodes.
3. Pain around the ribs is also attributed to the direct compressive effects of enlarged lymph nodes on the musculature of the chest wall.
So, kindly consult your treating Physician & discuss regarding this.
The biopsy reports will be helpful in deciding further plan of management.
Kindly let me know if you have any further queries.
You can ask me a direct query on this website using the below link: http://www.healthcaremagic.com/doctors/dr-polash-sannigrahi/64925
Wishing you a good health.
Thanks & take care.