Thank you for using JustAnswer.
I'm sorry to hear about your situation. Generally speaking, no, they can't just pull you over, stop you, or otherwise detain you for no reason at all.
In Delaware v. Prouse, the Supreme Court considered the case of man prosecuted for marijuana possession. (440 U.S. 648 (1979).) In the course of a traffic stop, the police officer had seen marijuana on the defendant's car floor. The officer testified that he hadn’t seen the defendant’s vehicle violate any traffic laws before he conducted the detention. He hadn't observed any equipment violations, nor had he witnessed any suspicious activity. He enforced the stop only so that he could check the driver’s license and the vehicle’s registration. He wasn’t acting in accordance with any established guidelines or procedures. The Court held that his kind of “spot check,” left entirely to the police officer’s discretion, is unconstitutional.
Now the remedy for evidence procured without probable cause is "exclusion". That is, if there was any evidence or anything that resulted in the stop, it would be excluded from the case. BUT you have to request that it be excluded prior to the trial or at the time that the evidence is being offered, otherwise the objection is waived. It's not "automatically" excluded, and if you don't ask for it to be excluded prior to being admitted, then it can and will still be admitted. Only if you had asked at the time to have the evidence excluded (and been denied by the judge) would you have something to complain about on appeal.
Hope that clears things up a bit. If you have any other questions, please let me know. If not, and you have not yet, please rate my answer AND press the "submit" button, if applicable.
Please note that I don't get any credit for the time and effort that I spent on this answer unless and until you rate it positively (3 or more stars). Look for the stars on your screen (★★★★★). You may need to scroll left/right/up/down to see these stars, but note that the rating is what closes out this question, so it is necessary that you do so.
Thank you, ***** ***** luck to you!