Definitely get in to see your doctor and to be honest, if you have been having any other symptoms besides the lumps, ie: tired, bruising, weakness, fevers/colds etc I’d go to an Urgent Care or to the ER. I wouldn’t mess around or wait. Get blood work and ultrasounds and X-ray immediately. 

Hi Louise,

N.B.  I'm not medically qualified, I just have a reasonable understanding of how the body works due to previous medical studies.

Your underarm lymph nodes are a 'clearing' pathway for 3 or 4 parts of the body.  They can swell up due to simple infections and, of course, due to cancer.  However, in terms of breast cancer and how it affects lymph nodes, your right breast would affect your right lymph nodes and your left breast your left lymph nodes.  If I had a lump on the one side I would see that as, generally, more indicative of the possibility of cancer than having lumps on both sides.  The appearance of lumps on the other side would actually relax me slightly.  That's not to say it's impossible for it to be cancer of course, but the presence of the lumps on both sides is, to me, a preferable sign.

Going away from cancer... I had a mosquito bite last year that developed into cellulitis in my left arm, that caused my underarm lymph nodes to swell significantly.  Lymph nodes can swell very quickly in response to infectons, it's their job, even infections that you don't yet know you have.  Swollen lymph nodes on both sides could indicate an infection somewhere in your body away from the breasts.

It's still very important to get these lumps checked out, I just want to get across that by no means do these lumps mean you have cancer.  There are many far less serious things it could be, so I hope that puts your mind at ease a little while you wait to get them checked out.  If it helps any I used to have 8 swollen lymph nodes around my neck (my cousin had 11 at her worst point).  Neither of us ever got a diagnosis for what was causing them, although when they first appeared we were both very run down, but they persisted for years.  My cousin no longer has any swollen lymph nodes in her neck but 15 years on 2 of mine are still swollen (very gradually going down).

I'll just reiterate that swollen underam lymph nodes does not automatically mean breast cancer, and with the presentation being on both sides it is far more likely to be something less grave.

Get them checked out, that's a must, but do not over worry yourself.

Take care,

LJx

Would love to hear how you got on. I'm surprised you weren't sent to the hospital straight away. I have had all my lymph nodes removed on one side under my arm .