2 1/2 yr old congested

Well my husband went to a pharmacy while I was working because when my daughter woke up she was very congested and she will be 2 1/2 towrds end of next month and they told him to give her childrens mucinex.  Well of course he did buy it and he started giving her only half a dose but she seems worse now.  Also before giving her medicine she was complaining her back hurt and sometimes should would cry about it pointing until we would massage it a little.  Now I have not felt anything wrong but can she be starting with asthma instead of it being allergies?  What should or can I do?

[Diva2317]

You might have better luck with children's Tylenol, especially for the back pain. I would also call her pediatrician and ask their advice, they may want you to bring her in for a more thorough diagnosis.