I can understand about wanting to wait to get fitted. You might want to go ahead and get fitted now. I got fitted when I bought my bike knowing that I would most likely have to get refitted once I got used to my bike.

Will your shoes come soon? Try to get fitted after your shoes come since the pedal height/shoes can contribute to a proper fit. I switched pedals/shoes last week and did not get refitted. My knees started to hurt. So, my cycling buddy adjusted my seat since my new spd-sl pedals sit up higher than my old spd pedals did. Made a huge difference in pain and energy transfer.

Sounds like you are cramped. If you still feel pain after a proper fit, you might have to see a doctor to rule out anything serious or to confirm rest is needed.

Best wishes!