What Causes Penis Discharge With Ejaculation Difficulties?

hi, yesterday i went to the toilet and noticed that a little bit of white stuff came out my penis. this had happened before and i got checked out and i didn't have anything. in the mornings it can be a little hard as its probably been like it all night..? i have been circumcised and find it hard to ejaculate. is the white stuff to be worried about and would you say to go get checked out?