Hello,welcome to HCM,
description given by you about amovable mass/growth near the neck can have several possibilities
1.soft swelling suggests-a gland(thyroid/lymph
node) or a bursa(fluid filled sac near joint (normally present in small size)
2. a hard/firm swelling suggests a bone growth(immobile)/hardened gland due to calcification of above
3. could be a tumor
4. diagnostics like an Xray/thyroid scan and blood tests should put a finger on the problem .
hope this clears confusion and you can visit a physician with some clarity Happy to help.