Welcome! Sorry you're having such a rough time and that the prospects are scary. I hear you!
The 3rd sticky at the top of this thread lists the usual symptoms that lead to a lupus dx.
Have you seen a dermatologist about the itching? Anything new in your environment that your could be allergic to - new house, new car, new clothes, new cologne, new detergent, new medicine, new pet. new flea powder?? Have you had an allergy workup?
I've never heard of one sided pain - except when I had an allergic reaction to Celebrex just before my lupus dx. Any chance you're on it? Before I was put on it, I had two spots (one on each forearm) that were red, about the size of a quarter, raised edges, and no itching. After being on Celebrex, those spots multiplied until it looked like I had leprosy (or what I imagine that looks like) from fingertips to elbows, bilaterally. In the following two weeks, my hips, knees, and ankles took turns swelling painfully and I couldn't stand up for more than 20 minutes due to leg pains. When I saw my rheumie for the first time, he promptly deduced I was allergic to the Celebrex and once off of it, all of the rash, pain, and swelling went away and has not returned. As it happens, many folks with lupus become allergic to sulfa and to Celebrex because it has a sulfonamide in its chemical makeup.
Another huccup about lupus is that the sunshine often makes all of the aches, pains, and fatigue much, much worse. Sunshine can cause a facial rash, too. I'm very sensitive to heat, too. Does any of that sound familiar?
Have you seen a good rheumatologist yet? A good one is one who treats lots of lupus patients, so is tuned in! If not, that might be where to go next.
I vote no lymphoma!
Wishing you well - Barbara