This is the fourth amendment. http://www.lectlaw.com/def/f081.htm
To answer the question would require books and books on this issue and the law applied to a set of facts in a given case. There are thousands and thousands of cass interpreting the Fourth Amendment.
No, the fourth amendment does not restrict the police in certain situations from searching your case. There are instances such as, for example, plain view and reasonable belief.
I don't know of any lawyer who could answer your question as written. Call a lawyer and have a professional consult. Could you sue the police? Sure. Would you win? Not based on the facts you've set forth.
Just a suggestion and for future reference: don't believe everything you hear.