The lumps in elbow and knee would be fibromas.
They are benign tumors.
You cosult surgeon for perfect diagnosis and treatment.Biopsy
may be done to reach to the diagnosis.
If they are embarrasing , the may be surgically excised under local anaesthesia.
And you can be free of swellings.
You are right, nausea
might be due to tension and mental upsets.
However, you consult physician.
I hope you got my answer.
Dr. Ilyas Patel MD