sinus pressure and digestive issues

I went to my doctor for what seems like a whole body wide attack. I've had some of the symptoms for a few months now while some other symptoms have just recently developed. There's no correlating lifestyle changes that can explain them, so my doctor said one of the top things to look for when systemic symptoms appear is some sort of allergic reaction. I've been scheduled to see an allergist for testing, but my appointment isn't until mid-August.

Here's a list of my symptoms (** denotes severe):
neck pain
jaw pain
red eyes
throat irritation
sinus pressure**
joint pains (mostly knees, but sometimes elbows)
digestive issues** (greasy stools, loose/powdery stools)
abdominal cramp/pains
rashes on my scalp, temples, sides of neck

I dunno, kinda anxious to get answers to what's going on with me. I've been in and out of the doctor's place so often this past half year without any real answer. Hopefully this allergist will give some insight.