Over-conditioning does cause curl "relaxation" and when too much oil is used strand separation and frizz can happen. But since you didn't mention any of that at first I thought it could be from dryness. However, jojoba oil is better tolerated by our hair because it's the one most like our own, it's worked to prevent frizz in a lot of people (and so has coconut oil). You can still try the spray bottle, even if it's just plain distilled water because this time of year most people's air is quite dry and that sucks moisture out of our hair.
2A/3A, medium length, layered, colored dark/medium ash blonde - "CGer" since April '02.

"Converting the 'curlskeptics' one curly head at a time..." HWHC