Cap has started stopping in the street!

hi again,
it's been a while since I was last on here and would like to extend my warm wishes to all those who helped an guided me last time because I've taken all your advice and Captain is coming on in leaps and bounds.
He has, however, just started stopping in the street on a walk if he doesn't want to go down a particular road. I can't decipher whether it's stubborness and him wanting to go a particular way because all the girlies are in season and all he seems to want to do is sniff the ground. Other times he seems nervous about something so I stop and fuss him then say "this way then" and he comes. it's really frustrating and I don't know what to do and I don't want to drag him on his harness. any ideas?? thanks guys!
Emma and Captain xx

Have you lead-trained him? Work on getting his attention - use treats and voice - and build this up.
When you have his attention, reward and walk on. Interact with him on walks more. Do more. Work on Sit at roads, Wait outside shops etc. Make your walk a training session and make it interesting for him.