Make sure that the cam lobe is on the 'heel'. The valve beside the stuck one should also be open. Keep in mind also, that these valves bend very easily.
I have read posts on here where people were able to use various home recipes to free up a stuck valve. I tried those things, and going through the intake opening as you have. I let MMO, trans fluid and WD40 soak in the guide for days. In the end, I had to remove the head to free up the valve. Hopefully, you'll have better luck with the other suggestions than I did.
Mike