Not getting erection from last 2 weeks.

I am not able to get proper erection from last 3 weeks while am trying to masturbate . I never had this problem earlier and i used to masturbate once in week/two weeks from last many years .I was able to sustain erection for atleast 30 min-40 min and ejaculate . Since last 3 weeks I am getting slight erection and it's becoming soft within a minute or no erection even when i am excited . Observed morning erection some times though . Also from last 3 weeks I am having slight pain in my right heel bottom while walking . Total cholesterol -217 , triglycerides - 179 . Have No diabetes or any other problem , not taking any medication. I am non smoker, non alcoholic . Am doing light exercise atleast 20 min . I don't have any stress , depression etc . Please suggest