Hmm, I'm afraid that you don't want to take tinkerbell23's answer too much to heart. In the UK, specific pharmacies within a particular county health authority are allocated to dispense opiates such as methadone. In effect, this means that in a medium sized UK town, there may be just one pharmacy that's licensed to hand out methadone to addicts. What this means is that in reality, there's a good possibility that your son may never work in a addict methadone dispensing pharmacy, so don't be too concerned about this.
Pharmacists are not personally intimate with patients; that's the task of medical professionals such as nurses and doctors. Stoma and truss fitting services are confined to advice on fitting within a private consultation facility at the pharmacy as are advice on other medical appliances. Pharmacists are not licensed to involve themselves in "personal interaction" as you put it.
By and large, the extent of these demands upon the pharmacist depends on the nature of community served by the pharmacy. The throughput of clients in a busy, major town pharmacy owned by one of the major companies is totally different from the village pharmacy that's served by only one local, possibly, elderly GP whose prescribing habits are predictable from the pharmacists point of view.