Hello Lisa. Thanks for your query.
The lump on the inner side of your elbow just above the crease can well be tendonitis
. It may be a cold abscess, although you deny having fever and night sweats
. Xray, Ultrasonography
and if required an MRI and a FNAC/Biopsy will rightly diagnose your condition. For pain, have some rest, restrict movement and have analgesics for the time being till you meet your orthopedician. Be calm and take care.