hai, Your problem seem to renal calculi.(kidney stone). possibly the stone will be traveled in ureter and lodged in the bladder output opening(internal urethral orifice.) The prescription given by the Ayurveda doctor is indicated to your problem. metallic taste may be felt because of the medicine.it will not harm you unless medicine prepared by GMP certified Pharmacy company. Metallic taste in medicine differs in every individual.tablet neeri contains (ayurvedic medicine) contain essential minerals and metals(annabeedi,bhasmas)etc.it will cause metallic taste. no side effects reported.safe to use. No need to worry.if your groin and stomach problem didn t solve within 1 week consult your doctor again. Thank you hope i answered your query.