You are very welcome.
Thanks for the further information.
This is unlikely to be serious or life threatening. So please do not worry at all.
This does not seem to be kidney infection (fever, burning urination are the symptoms). There is a small possibility of it being a kidney or a ureter stone (ureter is tube joining kidney and bladder). But usually pain is constant, severe and is unrelated to the posture and does not subside on lying flat.
Numbness in stomach point to a pinched nerve in the back or ACNES (abdominal cutaneous nerve entrapment syndrome). The diagnosis can be confirmed by the subcutaneous infiltration of the local anesthetic like xylocaine. If the pain disappears completely, this substantiates the diagnosis. Abdominal wall pain can occur from nerve entrapment syndrome, irritation of intercostal nerve roots, anterior cutaneous nerve entrapment, rib-tip syndrome, myofascial pain and trigger points. Your doctor should consider these abdominal wall problems also,for your pain (especially in the absence of the visceral symptoms like nausea, vomiting, constipation, bloating etc).
You should avoid any kind of lifting till the symptoms subside (despite some are painless). With your further description, I would still keep it as a spine and muscle issue. Warm compresses or heating pad would be helpful, so you may consider it.
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