Pregnancy Test

Is it really important to do a pregnancy test with the first urine in the morning?? My period is late by 4days. I'm TTC#1 from around six months. I do not have any obvious symptoms. I only have lower back ache and light cramps. Is there a chance to be pregnant even without the symptoms? Update 1: Tested last night but it was negative :( I'd drank a lot of water before. I'll wait for another 2 days and test again if AF doesn't show up. Thanks for the help ladies!!