I was told by a fertility specialist that i didn't need my tubes checked because i have been pregnant 4 times in the last 4 years. could they have gotten blocked since my last pregnancy (11 months ago, miscarried)?

Possible, not likely: I would tend to agree with your fertility specialist; tubal factor infertility is always possible but not likely if you have had four vaginal deliveries in 4 years. Take Folic Acid 1-5 mg daily and good luck!

Unlikely: It is unlikely that your tubes for blocked working last 11 months unless you had severe pelvic infectio during that time.