Whenever I play osu! after a few beat maps my neck starts to hurt, don't know why it's like I've been straining for so long and it's really uncomfortable. Just want to ask you guys if you have the same problem Q_Q
You're probably just sitting in a position that your body does not like staying in for long periods of time, the same thing can happen while playing DS or really anything if your neck stays in a strange position.
Could also be too tense while playing, getting real excited and clenching up etc.