Feels Like Sunburn Under Right Armpit-come/goes Periodically

I was diagnosed in 12/06 with mild case of crohns. I do not know if any of this is related to my disease or it is something new:
1. White sore on roof of mouth. My doctor injected with steroid shot.
It went away.
2. The last two years same time of month June I have had
bronchitis. This past year it took over a month to go away.
I had to do two z packs. I felt like I had asthma.
3. I am losing my job due to downsizing at work, husband took new job
without insurance, feeling stressed finding a job. Armpit right side
feels like I have a sunburn underneath of it. There is no rash, nothing.
The pain can be intense. It hurts more when I walk around (sweat).
THis happened to me some time ago and it slowly went away.
It has now returned with recent events.
Is this related to chrons, stress or could it be something worst. I had a
chest xray this year when I had bronchitis. It was normal. I had
mammogram last Sept. It too was normal. I am having no stomaches,
but diarrhea yes.

Confused and not sure what to do to help my symptoms.
Thank your listening.