"个人问题" generally can refer to one of two things: 1. personal/private reasons (as you pointed out) 2. due to fault of my own, my own incapability "个人问题" is just a general expression to indicate that the problem is on your side/end. In a relationship, it may imply a lot of things... But ultimately, you're saying the problem lies with you. If we wish to be more specific, we could say 私人缘故/原因 to indicate that an issue is of private/personal matter.

两个都是对的。如果口语中听到“你个人问题解决了没有？”，一般就是在问婚恋状况，这是比较委婉的问法。

personal issues. private matters

个人问题，这是个人问题，不是集体问题，这个时候是personal 其他情况一帮是说 婚姻or结婚对象

On its own, 个人问题 can be translated as "problems of an/the individual". The meanings are inferred by context.