Oh yes, in many published books I've seen horrid sentences, wrong names given to even minor characters, misspelled words, missing words in general, errors in grammar usage etc. It's all there. Maybe they don't have enough people to look over their work before it gets published. You are too close to your own work, even if you went through your story several times before, you'll still find typos and such. I know I have with my stories. Having two or even three sets of eyes read your story for those things would be very useful in the long run. People you choose to edit/beta/proofread (whatever you want to call it) need to know a thing or two about the rules of writing, proper grammar usage, spelling, sentence structure etc. You can't hand it over to your best friend, who may know nothing about writing stories or writing at all, only to have them say, "That story was very good!" It's best to find those who are knowledgable and know how to write.
-Kristi