What happens with oversecretion of parathyroid hormone?

Hypercalcemia: You get "hyperparathyroidism", which results in an elevated level of serum calcium, and decrease in serum phosphorus levels. With continued elevation, you get renal stones, abdominal pain, headaches, psychriatric symptoms, bone pain, etc.

Stones bones groans: Main symptoms are related to calcium in the urine (kidney stones), abnormal bone metabolism which may lead to pain, osteoporosis, or even fractures, memory disturbances or mood swings. There are data suggesting that untreated hyperparathyroidism may be linked to excess cardiac mortality.