what you need to figure out first and what machine type you need. since you didn't provide any information on your skin and hair type, it's impossible to tell you this. you need to figure this out first before looking for a clinic. once you do, you can use the search feature to find previous recommendations if any. also, you can use manufacturer website provider searches and you need to check out 3-4 clinics at least.
please read the FAQs and check out the laser portion of this forum to learn more about LHR in general first. you need to be an educated consumer as many in this business still just bought a machine and dont know what they're doing. so try to be as informed as possible on your own.
http://www.hairremovalforum.com/faq.cfmp.s. shoulders are a notoriosly hard to treat area, so being informed is even more important for you.