Yes, the bar draws out the vowel sound.
し is "shi", not "chi".
What did you use to learn hiragana? No offense, but you seem to be confused about some of the most fundamental concepts regarding how hiragana works.
Here is an online guide that many people seem to recommend these days:
Learn Hiragana: The Ultimate Guide
I suggest that you read it thoroughly and make sure you grasp everything there before you try to practice reading with native materials.