I has not a lot in common with illnesses, but with finances. The pharmacy in a dream, according to the old interpretation should predict a coming weeding with someone rich. Sometimes, this sign warns us against people who do not deserve our trust. It may also mean that you are looking for support and the way to find happiness and prosperity.
see from the outside: a possibility to marry with rich person
be in pharmacy: success
enter the pharmacy and buy some medicine: financial loss
plan to visit a pharmacy: you are too independent and you never allow to help yourself
stay in a queue in a pharmacy: you will relieve yourself from problems
talk to the pharmacist: improvement in finances, rich partner, marriage with rich person