Gall bladder has the function of collecting, concentrating and at the right time, releasing bile. The body does not suffer if the gall bladder is removed. Acute or recurrent cholecystitis is an indication for cholecystectomy. It is done in the USA by laparoscopic technique. Laparoscopic surgery needs the following conditions: No prior surgeries within the peritoneum, patient should be free from significant lung disease as the abdomen is inflated with gas. 

Gall stones are cholesterol stones in 95% of patients (thus radiolucent). If the stone is very small and single, it may be dissolved using medication (Ursodeoxycholeic acid or Ursodiol). In other situations, it needs surgery.

Murphy's sign - wincing on taking a deep breath if the palpating hand is kept in the RUQ.

If the patient has fever, chills, rigors  and jaundice, the diagnosis is going to be Acute cholangitis.

Diagnosis of Ac. cholecystitis is made using clinical information and by a combination of either ultrasound or HIDA scan. In the HIDA, non-visualization of the gall bladder constitutes an abnormal finding.

How to deal with Asymptomatic gall stones.

Also remember some important pointers about rigors:
The commonest causes are: Pyelonephritis, Pneumonia & Cholangitis.