Who

 Would know 

I am a

 Elvis Presley fan

Yall

 Foul

Is it

 Elvis Presley 

Hello

 Hi

.....

 Musco Stella skeletal ortho gym 

I should

 Be at a gym 

To let you know

 If 

Then

 Well I didn't know how much pain I was really in

Of

 The gym 

Now had you told me

 I first would have wanted a tour