I submitted a paper five months ago. Should I wait a little bit more for a response?
It differs case by case, but journals take a while before acceptance and publishing. Once I waited a year for a high ranking journal! You can always contact the editor and ask about the status of your journal.

Advice On Your Thesis and Submitted Material: You can definitely cite the submitted material within your thesis. Don't forget to add the (Submitted to X) at the end of the citation.