I really don't know what to tell you for sure about these multiple lumps.
The only thing that comes to mind,( guessing here) is that they could be cysts or fibroadenomas (both benign in nature) that have appeared probably by an increased hormonal changes in your body.
Indeed Fibrocystic breasts condition could be the cause of these lumps.
The lumps around the collarbone area could be swollen lymph nodes that become more prominent due to perhaps an infection ( past or present) somewhere in the body.
In my opinion I would have worried more if only one lump had appeared,but multiple ones are less likely to be worrisome.
It's a good thing though that soon you are having an Ultrasound to clarify this problem and put your mind at ease. Hopefully the findings will be negative for any serious condition.
Please let us know what the test has revealed,by typing your comment below the answer/s you have received.Thank you and wishing you all the best!