Need help with bench press/chest

[Sree]

My bench press has not increased since the past few months. Im stuck at a plateau maybe? I don't have a spotter usually, so I 2nd guess myself on how much I can push myself, especially for the bench press. Right now I start of with 145 on a good week. and goes along these lines:

1st set: 145lbs/ 7 reps
2: 145/ 5-6 reps
3: 150/ 4 reps
4: 155/ 2 reps

All my other lifts are going up though.
Squats: 260 lbs on last set
Deadlifts: 275 lbs on last set

My chest is really lagging...I don't know what to do. I did some extra sets for my chest the other day, hoping it'll make some difference(worked lower/upper pecs)