It's been awhile since I've seen the movie but if I remember correctly, Steve is trying to find the Winter Soldier, whose real identity is that of his friend Bucky, who was thought to be dead after the first Captain America movie.
When Sharon says "Tips have been pouring in since that footage went public," she means that people have been calling in to provide tips, or information, about the winter soldier. Its typical when a crime occurs that law enforcement agencies will release an image, or a video clip, and set up a telephone line for people to call in if they've seen or know the individual in the image/video clip. Known as a tip line or a hotline.
"Everybody thinks the winter soldier goes to their gym." The people calling in to the tip line think the winter soldier looks like a member of their gym.
"Most of its noise." She means that most of the tips being provided by people are dead ends, useless and incorrect information. The tips being provided are just noise or distractions that take time to corroborate and don't provide any meaningful information.
I hope this helps! :')