What is your age?
How is the rest of your health?
Do you take any medication or have any previous problems?
Any fever during the day? Any cough, recent weight loss?
Night sweats and muscle aches could be an indication of an infection of some type. This is certainly something that would need to be investigated to rule out the serious infections such as TB. The lack of cough and weight loss is a good sign. Ask your doctor to run a differential white cell count as this may be helpful.
Other causes of night sweats include nocturnal hypoglycemia which is low blood sugar overnight so you may want to consider whether there has been any changes to your eating pattern.
I would also want to rule out hormonal problems as night sweats are associated with estrogen deficiency. You should also have thyroid function tests to rule out a thyroid problem.
Finally wellbutrin can cause sweating, and Crestor can cause muscle pain so you need to discuss with your doctor whether the medication may be related to your symptoms.
Sudden onset is more likely to be associated with infection. So you may have a gastroenteritis but I would expect you to have some gastric upset symptoms as well as the sore stomach. Have your bowel motions been normal?
We would need more information to be able to reduce the options down to a specific cause and you need to be checked over. I would also like your blood pressure checked to exclude a problem with your adrenal glands.
Menopausal night sweats will occur often with mood swings, daytime hot flushes and other signs of hormonal disturbance such as erratic periods.
If you are constipated then buscopan will reduce spasm but may make the constipation worse. I would recommend that you stop the buscopan and use a laxative or stool softener to help empty the bowels. Any severe pain and fever you must go to ER as there is a risk of perforation with bowel obstruction in severe constipation.
Opioid based painkillers will also make matters worse.