From www.MayoClinic.com (a site I trust):
"Pink eye (conjunctivitis) generally remains contagious as long as the eye continues to tear and produce a discharge. Signs and symptoms of pink eye usually improve within three to seven days. When tearing and discharge are no longer present, it's appropriate for a child to return to school or child care."
"Treatment for viral conjunctivitis
There is no treatment for most cases of viral conjunctivitis. Instead, the virus needs time to run its course — up to two or three weeks. Viral conjunctivitis often begins in one eye and then infects the other eye within a few days. Your signs and symptoms should gradually clear on their own."
There is no mention of using shampoo and I can't imagine that this wouldn't irritate the eye more. Regular saline eye drops can be used to keep the eye moist.