Well, there is no reason to think it's lymphoma - that's why your doc isn't concerned about that. I don't know of any other cause for your symptoms other than a mast cell disorder. You don't have to match every symptom, or even match the common ones. It's very variable.
I'd guess that a rheumatologist is your best bet at this point. Common tests for inflammation (CRP or ESR) might or might not show high. There are 24 hour urine tests for metabolites of mast cell mediators, like prostaglandins.
Oftentimes, there is a clinical diagnosis, which means that you get better from treatment for a particular disorder, but without having any positive lab tests and every other possible cause having been ruled out.
Let me know how it goes.
Here is a partial list. There are some famous names there (Brigham and Women's and also Tufts in Boston, MD Anderson in Texas, Mayo etc), so you can know this is not just some wacky offbeat thing.
https://tmsforacure.org/mast-cell-disease-treatment-research-centers/
Unfortunately, it's not as simple as going to just any rheumatologist or allergist. There is not one definitive test, or two or three. That's how it is with complex immune conditions.
Or, by luck you might just happen across a doctor that is familiar with all of this. It could even be an ER doc.
There are some docs that specialize, they would be generally found in large med centers, especially at universities.
Treatment usually starts with antihistamines, then involves adding other meds until a successful regimen is found to manage the symptoms.
Do you have a history of bad allergies?
Good, but since it is a very complicated disorder, this can't be short or easy. Many patients go years seeing various doctors before they hit on this. It will take research on your part.
Start here at about the one hour mark:
https://youtu.be/82dmZhCBuBo?t=59m54s
You don't have to get into the history or the genetics of it at this point. You want to see if the symptoms sound like you.
Btw, I don't mean that you can't catch your breath as if you've been running hard; I mean that patients can't seem to get a good, deep breath, even though they are normal in tests. It's a feeling.
"my memory is really bad"
Another offshoot of a mast cell disorder is called "brain fog". Do you sometimes also have trouble doing something like multiplication in your head, can't concentrate no matter how hard you try?
Anxiety can also be related. Bipolar can be associated, too.
Or would you prefer to discuss it with me for starters? I'd be very happy to help. There's no need for you to just keep suffering and not knowing what's going on. The causes are very likely physical. The mast cells produce over 2 hundred powerful biochemicals that can have all kinds of effects. Lots of patients afflicted by this take years to get diagnosed.
Hi, do flush a lot?
Since you've been to doctors and they haven't made any diagnosis then what comes to mind is that you have an unusual immune system condition - not lymphoma.
Itchiness, headache, exaggerated response to insect bites, bome pain, trouble catching a good breath... these can all be symptoms of a condition involving immune cells called mast cells. A lot of it involves histamine. But mast cell disorders aren't widely known yet, even among lots of doctors.
Are you willing to watch some videos made by doctors who specialize in this? You can at least know that you are not alone and that many other people suffer similarly. It is real, it's not imaginary. How does that sound to you?