Widow Asks About Tax Treatment of Late Husband's Pension

[1] My personal information is as follows: I am a widow living on my husband's personal pension from his previous place of work, which is issued in United States. I hold dual citizenship with Canada and United States. I was born in Canada but I have been living in United States for 16 years.

[2] What my question is, if I should move back home to Canada would I have to pay Federal Income Tax on the pension I receive from my husbands pension plan.

[3] I contacted the Canadian Internal Revenue and I was advised that I would be paying taxes on any income I have whether it be from the U.S. or Canada if I should back to Canada.

[4] What I want to know is will the U.S. also tax me if I should move to Canada?

[5] Any information you can give me would be greatly appreciated.