Is it normal for my arm to hurt a week after donating blood? feels like a muscle ache in ac area and is still bruised pretty badly

Unusual, But: Not unheard of especially considering the bruising you describe. You might want to call the donation center to let them know as well as ask their advise. Usually the ache will go away when the bruising does and that may take a couple of weeks. Oh and thank you for donating blood since it helps save lives and some people are unable to give blood because of their health or other concerns.

Likely yes.: The area of the AC fossa is sensitive. The needle positioning might have caused a contusion and is evidenced by the bruising. The bruising alone can cause pain due to heme in the tissue. So yes, a week is not out of the question and all the pain should resolve when the bruising is gone.