If y husband passed and there is no Will but only a bank account with his son is listed as beneficiary, do I have any rights to the money?

Under most states you have a statutory forced share to claim against his estate.  This amount is usually 1/3 of his estate.  The assets that are subject to this right are called his augmented estate.  The real question here is whether this account is part of his augmented estate.  If it is you would be entitled to 1/3 of it.  You need to meet with an estates lawyer to go over all the facts and details here to get a definitive answer.