Can i take legal action against a school district for searching my son's cell phone after being taken away in class?

Probably not. The school had the right to take your son's phone because he broke the rules, and the courts have consistently ruled that schools can subject students to non-intrusive searches, to fight drug use, etc.

Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.