Hello. Another declension question for you wonderful people out there im deutschen Sprachraum. In Intermediate Lesson S2 #31 - Sometime, Somewhere in Germany, This Could Happen to You! there are yet again a few declensions that I just don't understand. They are:
1. Ich habe seit ein paar Stunden extreme Bauchschmerzen. I thought that seit triggered a dative ending. Why is ein not einem?
2. Was für ein Schmerz ist es? My dictionary says that Schmerz is a masculine noun. Why isn't it written as Was für einen Schmerz?
3. Haben Sie irgendwelche anderen Symptome bemerkt? Why is it anderen and not andere?
Thanks a lot in advance!