Hi, chocokid, and welcome. Lupus is an "autoimmune" disease, meaning your immune system mistakenly attacks your own cells. Everything from skin to major organs (kidneys, brain, heart, lungs, etc.) can be affected; and constitutional problems (pain, fatigue, etc.) are very common. Like other autoimmunes, it's not contagious. Nor is it inherited, although people with first-degree relatives with lupus have higher odds. It ranges from mild to severe, but today can usually be managed successfully by specialists (rheumatologists are primary, and other specialists are seen if needed).
It's hard to diagnose because symptoms are so wide-ranging, and because they come & go, in flares. There's an established set of criteria you can read in one of the "sticky posts" (permanent info posts) at the top of the thread list. To be diagnosed with the "systemic" form of lupus, you generally have to meet at least 4 of the 11, not necessarily all at once. (Think of checking each off in indelible ink, once met.)
The other "stickies" discuss symptoms, tests, etc.
When you say you were tested for arthritis, which tests were done & which came back on the higher side? (I'm curious because there isn't any one test for arthritis, plus there are over 100 forms of arthritis.) When being tested for lupus, basic panels like CBC (complete blood count) are usually run, plus specialized autoantibody tests.
There is no "typical" lupus patient because it varies so much. That said, over many years, I had hair & weight loss, rashes (but not on my face), severe headaches, pain, fatigue, low-grade fevers, and GI & urinary problems. Some of my basic blood tests were off at times (low B-12, high sed rate, depressed white blood count). I became very photosensitive, meaning sun brought on not just rashes, but overall problems too. On specialized blood tests, I tested positive for a specific autoantibody seen in lupus, plus skin biopsies also came back positive for lupus. My first probable flare was in early teens.
Anyway, I'll stop now, to give you a chance to read the stickies... then I hope you post again. Sending my best wishes to you, sincerely, Vee