She may be lonesome or could be responding to sounds from outside.
You might try leaving the tv or radio on low for her.
This site has a list of symptoms at the top that you can scroll by to get to the ideas on how to help a dog with a separation issue
http://www.wagntrain.com/SeparationAnx.htm
and scroll down to Here are some things you can do to help.
See if that works to resolve this.
You might want to consider doggy daycare for her too one or more days of the week if there is a good local one as that helps tire a dog out making it easier for the dog to rest on the days she stays home.
Hope this helps you!
Thankyou for your help. These suggestions I have thought, so what i suppose i really need help with is how do I train her to understand it is ok to be alone when we go out and that she will be ok without her humans for company. at this age is it too late or are there some tricks to help her be ok when she is left home alone
I gave you the info on training 'tricks' here just click on the link
No it is not too late to train a 4 month old puppy.
The older she gets the more need she will have for exercise so plan on increasing that for her to help keep her calm.
You may also want to join a basic obedience training class with her as training can help a dog be less stressed once you are seen as the leader and once the dog gets more used to doing what you want instead of what she wants.
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics