Chest wall lump

Been having dull intermittent pain on my left side of my ribcage and last week I found a lump in my intercostal space. 21F. Diagnosed with a Hashimoto’s thyroiditis (euthyroid, nonmedicated). Bilateral joint & muscle pain in knees and elbows since childhood. Pain areas have progressed to hips, wrists, and back. I have muscle knots all over my back, sometimes get sharp pain in my lower ribs that worsen with inhalation and lasts less than a minute. DsDNA=10, ANA positive cytoplasmic 1:80, bilirubin has been mildly elevated (highest was 2) for at least a year off and on, random bout of hypokalemia (3.1) in April 2025 causing palpitations, ear infection persisting for 3+ months (did not resolve with Rocephin, Dexamethasone, and Cefdinir), tonsils are enlarged with no sign of infection, claritin d and Flonase have not helped either. I get flat hives in hot showers and when stray hairs are stuck in my clothing. Albumin was low during hypokalemia, chloride was high, BUN was low, and it was an idiopathic episode (til this day I still don’t know the cause but I was in the ER for it due to intense and frequent palpitations). I frequently get racing pounding heartbeat with or without exertion, very random, seems somewhat correlated with posture/positional changes. I get weird mottling in legs after showers. Hands and feet are frequently very cold (20 degrees F less than my core body temp). I’ve noticed these symptoms with and without the medications I’m on, so I know it’s not the medications (MAYBE the birth control, that’s been the only constant med I’m on since 2019). Ferritin=13, dTIBC=425, Iron=123. Med list: 50mg spironolactone, 15mg adderall XR, 25mg metoprolol ER, larin fe 1/20 (skip period weeks, continue to new pack every 21 days), 400mg ibuprofen once per day maybe 3 times per week. Recently started Claritin D, Flonase, and amoxicillin (2 days ago).