The problem is what the underlying cause of what the murmur is. If it's cardiomyopathic, then the cause could be worrisome and require medication. But it isn't uncommon for a ca to have a heart murmer, have no health issues, and live a happy, long life without problems.
The one thing I'd be aware of is if kitty ever needs surgery, such as spaying, or something more complicated. Then the vet should be made aware of the issue so he can treat accordingly. Type of anaesthesia, among other medications, can be dangerous in such a circumstance.
And yes, some kitties don't take kindly to being harrassed...or, frankly, certain types of affection. I have one who's a friendly old teddy bear, as long as you don't pick him up. Do that, and he'll take a finger off. Like people, they have their own personalities, likes and dislikes. Respect them, yo'll get along fine. Don't, and beware going to sleep with the bedroom door open!! :)
Thinking About The Cat Attacking Me. I Think Its Just Natural. I Mean The Time The Claw Broke My Mum Was Provoking Her And Blowing Air In Her Ear. She Does Get Annoyed Quite Quickly. She Was Worse As A Kitten But I Personally Think Shes Growing Out Of It. Would Be Glad Of Some Advice About The Murmer Though.