Hello , i just read through your query and feel that your symptoms are attributable to the drugs which you are taking.
 I will list your symptoms and the drugs alongside which are causing those symptoms.
 1-Tight sensation in the leg-also called as 
myalgia occurs in 2 % of patients taking 
pravastatin.
2-Tight sensation in the leg-also called as myalgia occurs in 2-6 % of patients taking 
Bupropion.
3-Fatigue (low energy) occurs in 2 % of patients taking Amitiza,Zetia and 1-10% in those taking 
Olmesartan.
4- pain in legs occurs in 3 % of patients taking Zetia.
5-weight gain in 4% of those taking Bupropion.
6-
Cymbalta causes fatigue in 10-11% of patients, muscle spasms in 3%.
I know the list is big but the drug with most side effects and most likely cause of your muscle spasms is Cymbalta.
I hope i have proved to be of some help in answering your query.Goodluck.