My metoprolol tart 25mg went from a tiny orange pill to a bigger sized white pill could that be causing side effects? why did the look change?

Different generic: Your pharmacist probably switched brands of metoprolol. However, I would recommend that you make sure you got metoprolol and not another drug by mistake. To make sure that you got the right drug, you can use one of several pill identifier websites such as : http://www.drugs.com/imprints.php. If you did get the correct medication, sometimes there can be some variability in the actual potency.