I agree with Romiosangiovese, especially that definitly no shock collar needed.
Take him out on a long lead to somewhere without major distractions preferably to begin with. Take with you something he is keen on either food or toy. Toy is preferable because you can interact with him using the toy whereas food is quickly gone. Your intention is to make you the centre of his world, you have to be more interesting than other dogs, dropped burgers kids, cars etc. Starting easy with no distractions and the toy you are maximising his chances of sucess and make a really big deal every time he comes back. If using food give him several pieces as a reward. Only when he is coming back each time do you move on (gradually) to more and more distractions. Still keeping him on the line and not giving him any occasion of ignoring the recall command. The line is a safety net not something to haul him in on BTW. If he doesn't come, try calling and running off in the opposite direction which is pretty much guarenteed to get him coming to you. I would be practicing this a LOT, so he is getting maximum oputunities for finding out how exciting being with you is. Don't let him off, especially where there are any kind of distractions, until he is rock solid and even when you have a reliable recall, it needs practicing/reinforcing reguarly.
All my boys are entire (apart from Yogi who was castrated for medical reasons at 7 years) and all have good recalls. Yogi is a reactive dog too (to other dogs) so I put a lot of work in with getting his recall off other dogs solid. Once he was reliably coming away from general distractions (sniffs etc) I started introducing high level distractions. I didn't want to use other dogs but as he is mad on tennis balls I began with calling him away from one placed on the ground, then rolled, then gently thrown etc until he would come to me rather than go for the ball. It didn't happen overnight but I got him to a stage where I could call him away from running at another dog if the need arose. I try to avoid putting him in that situation when I can so he is not constantly being tested and it's more an emergeny proceedure.
However Epic's recall is far and away the best because as soon as he could come out on walks I practiced calling him back over and over again, every time giving him a reward and fuss until he could recall even when running full tilt in the opposite direction. Twice I've been very glad of having put so much work in with him as it has prevented him bolting. Most of the time I will call the shelties back, give them a fuss and treat and let them go off again - when leads go back on they get more fuss. I also have worked at putting leads on randomly during walks and then taking them off again so they never knew what was going to happen.
I'm not sure how you are using the clicker - it should be a marker for correct behaviour not a means of getting attention. So if Storm is trotting off on a scent and you call and he looks back or stops of even slows down then mark it with a click. If he has been used to the clicker he should then anticipate getting his reward and come back. That is not the recall part though as you are simply telling him to start with that any positive response to you calling is good. If he completely ignores the call and gives no sign he has heard then the distraction is too great or he has got too far away from you so you need to take it back a stage and maximise his chances of doing it right. From a small response you gradually increase the criteria before you click - so from a head turned back you then wait until perhaps he turns his shoulders or even turns round. The more exciting you are and higher the value of reward, the quicker he will pick it up but there is no point taking him out for the first time and either clicking before he has offered a response or waiting for a complete recall before clicking.
If you put your problem into a new thead in the Training section I'm sure lots of people will be able to give you more specific advice. It isn't easy but you'll get there don't worry.
