pain in the thigh after angioplasty

had angioplasty last month and 2 stents in the left and right arteries of heart and one in the right shoulder was put. till 5 days before the angioplasty i had a very active life, i used to work out in the gym for one and half hour, had an active work schedule with no complaints. suddenly i developed pain in the right shoulder which lasted for 2-3 days. my ecg showed variations and i was admitted to hospital and later angioplasty was done
after the angioplasty i have developed pain and burning sensation in the thigh from where the insertion was done.
my questions are
1. how come i had three blockages ? i never had any problem in my working out or climbing stairs or walking

2. why this pain ? my dr says to ignore it , it will go slowly but i have become very scared.
3. Why so many diet restrictions?
4. How will taking low salt help , I never had any BP problem?
5. How does taking fibrous food help?
6 does life expectancy decreases after angioplasty/
& wht is the life of a stent?