Has the vet seen the swollen shoulder?
Did this happen after any hard play or a sharp turn or a jump down from a high area?
Is the shoulder swollen at the joint or over the flat plate of the shoulder blade?
Does she get walked using a collar and if so what kind?
Thanks for the extra info!
If she has a lump over the flat shoulder blade it really should be evaluated by your vet.
It is possible this is due to a muscle strain and that might respond to anti inflammatories or a muscle relaxant.
It could be this is a tumor that needs removal and if it does getting it while as small as possible is usually the best choice.
It may be another fatty tumor that is in a poor location and restricting muscle action and so needs to be removed.
It could be this is an inflammation from an infection under the skin caused by a small puncture where there was only a tiny bit of skin damage but bacteria was left under the skin to grow.
If the feet are sore between the toes you may be dealing with an allergy issue.
You can read about canine allergies causing skin issues here
You may also want to have your vet check for a thyroid issue. Particularly if the sore foot areas start as a hard lump.
You can read about interdigital cysts here
Hope this helps you!
You can try a cold compress on the area if you think its inflammation only.
10 minutes on for a towel wrapped cold compress.
But I'd still plan on seeing the vet about it - might even be a reaction to an insect sting making her sore, or an inflammation in the joint making the muscle swell so an in person look by your vet is a good option.
If you found an answer helpful you can accept it and thanks!